Data transmission in carrier aggregation with different carrier configurations

ABSTRACT

Techniques are provided for aggregating carriers with different carrier configurations. The carriers may include both time division duplex (TDD) and frequency division duplex (FDD) carriers which may be configured such that control information for both carrier types is conveyed by the TDD carrier. In one aspect, an association between a set of subframes, including both TDD and FDD subframes, is determined. The association may operate to distribute control information for the FDD carrier over uplink subframes of the TDD carrier to achieve a load balancing. Alternatively, the association may operate to minimize a hybrid automatic repeat request (HARQ) feedback delay. The TDD carrier may provide resource grants for the aggregated carriers and the association may be used to identify subframes from both carriers which may be scheduled in a given DL subframe.

CROSS-REFERENCE TO RELATED APPLICATION

The present application for patent claims priority to ProvisionalApplication No. 61/663,468, filed Jun. 22, 2012, entitled “DATATRANSMISSION IN CARRIER AGGREGATION WITH DIFFERENT CARRIERCONFIGURATIONS”, which is assigned to the assignee hereof, and isexpressly incorporated in its entirety by reference herein.

BACKGROUND

I. Field

The present disclosure relates generally to communication, and morespecifically to techniques for supporting carrier aggregation in awireless communication network.

II. Background

Wireless communication networks are widely deployed to provide variouscommunication content such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

A wireless communication network may include a number of base stationsthat can support communication for a number of user equipments (UEs). AUE may communicate with a base station via the downlink and uplink. Thedownlink (or forward link) refers to the communication link from thebase station to the UE, and the uplink (or reverse link) refers to thecommunication link from the UE to the base station.

A wireless communication network may support operation on multiplecarriers. A carrier may refer to a range of frequencies used forcommunication and may be associated with certain characteristics. Forexample, a carrier may be associated with system information describingoperation on the carrier. A carrier may also be referred to as acomponent carrier (CC), a frequency channel, a cell, etc. A base stationmay send data and control information on one or more carriers to a UE.The UE may send control information to support data transmission by thebase station. In this context there remains a need for flexibletransmission and processing of control information for carrieraggregation.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

Techniques are provided for aggregating carriers with different carrierconfigurations. The carriers may include both time division duplex (TDD)and frequency division duplex (FDD) carriers which may be configuredsuch that control information for both carrier types is conveyed by theTDD carrier. In one aspect, an association between a set of subframes,including both TDD and FDD subframes, is determined. The association mayoperate to distribute control information for the FDD carrier overuplink subframes of the TDD carrier to achieve a load balancing.Alternatively, the association may operate to minimize a hybridautomatic repeat request (HARQ) feedback delay. The TDD carrier mayprovide resource grants for the aggregated carriers and the associationmay be used to identify subframes from both carriers which may bescheduled in a given DL subframe.

According to one aspect, a method for sending control information mayinclude determining an association between a set of downlink (DL)subframes including TDD subframes and FDD subframes of the respectivefirst and second component carriers and an uplink (UL) subframe of thefirst component carrier based on an uplink-downlink configuration of thefirst component carrier. The method may include generating controlinformation associated with transmissions on the set of DL subframes.The method may include sending the control information on the ULsubframe of the first component carrier based on the association,wherein each DL subframe of the FDD second component carrier isassociated with a corresponding UL subframe of the first componentcarrier.

According to another aspect, a mobile device may be configured forcarrier aggregation (CA) of at least a TDD first component carrier and aFDD second component carrier. The mobile device may include means fordetermining an association between a set of DL subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers and a UL subframe of the first component carrier based on anuplink-downlink configuration of the first component carrier. The mobiledevice may include means for generating control information associatedwith transmissions on the set of DL subframes. The mobile device mayinclude means for sending the control information on the UL subframe ofthe first component carrier based on the association, wherein each DLsubframe of the FDD second component carrier is associated with acorresponding UL subframe of the first component carrier.

According to another aspect, a mobile device may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The mobile device may include at least one processor configuredto determine an association between a set of DL subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers and an UL subframe of the first component carrier based on anuplink-downlink configuration of the first component carrier. The mobiledevice may include the at least one processor configured to generatecontrol information associated with transmissions on the set of DLsubframes. The mobile device may include a transceiver configured tosend the control information on the UL subframe of the first componentcarrier based on the association, wherein each DL subframe of the FDDsecond component carrier is associated with a corresponding UL subframeof the first component carrier. The mobile device may include a memorycoupled to the at least one processor for storing data.

According to another aspect, a computer program product may include acomputer-readable storage medium including code for causing at least onecomputer to receive a resource grant in a DL subframe of the firstcomponent carrier. The computer-readable storage medium may include codefor causing the at least one computer to determine an associationbetween the DL subframe and a set of subframes including TDD subframesand FDD subframes of the respective first and second component carriersbased on an uplink-downlink configuration of the first componentcarrier. The computer-readable storage medium may include code forcausing the at least one computer to send the control information on theUL subframe of the first component carrier based on the association,wherein each DL subframe of the FDD second component carrier isassociated with a corresponding UL subframe of the first componentcarrier.

According to yet another aspect, a method of wireless communication by amobile device may be configured for CA of at least a TDD first componentcarrier and a FDD second component carrier. The method may includereceiving a resource grant in a DL subframe of the first componentcarrier. The method may include determining an association between theDL subframe and a set of subframes including TDD subframes and FDDsubframes of the respective first and second component carriers based onan uplink-downlink configuration of the first component carrier. Themethod may include identifying, based on the association, a subframe inthe set of subframes for transmitting or receiving data on in responseto the resource grant, wherein each subframe of the FDD second componentcarrier is associated with a DL subframe of the first component carrier.

According to another aspect, a mobile device may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The mobile device may include means for receiving a resourcegrant in a DL subframe of the first component carrier. The mobile devicemay include means for determining an association between the DL subframeand a set of subframes including TDD subframes and FDD subframes of therespective first and second component carriers based on anuplink-downlink configuration of the first component carrier. The mobiledevice may include means for identifying, based on the association, asubframe in the set of subframes for transmitting or receiving data onin response to the resource grant, wherein each subframe of the FDDsecond component carrier is associated with a corresponding DL subframeof the first component carrier.

According to another aspect, a mobile device may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The mobile device may include a transceiver configured toreceive a resource grant in a DL subframe of the first componentcarrier. The mobile device may include at least one processor configuredto determine an association between the DL subframe and a set ofsubframes including TDD subframes and FDD subframes of the respectivefirst and second component carriers based on an uplink-downlinkconfiguration of the first component carrier. The mobile device mayinclude the at least one processor configured to identify, based on theassociation, a subframe in the set of subframes for transmitting orreceiving data on in response to the resource grant, wherein eachsubframe of the FDD second component carrier is associated with a DLsubframe of the first component carrier. The mobile device may include amemory coupled to the at least one processor for storing data.

According to another aspect, a computer program product may include acomputer-readable storage medium including code for causing at least onecomputer to receive a resource grant in a DL subframe of the firstcomponent carrier. The computer-readable storage medium may include codefor causing the at least one computer to determine an associationbetween the DL subframe and a set of subframes including TDD subframesand FDD subframes of the respective first and second component carriersbased on an uplink-downlink configuration of the first componentcarrier. The computer-readable storage medium may include code forcausing the at least one computer to identify, based on the association,a subframe in the set of subframes for transmitting or receiving data onin response to the resource grant, wherein each subframe of the FDDsecond component carrier is associated with a DL subframe of the firstcomponent carrier.

According to yet another aspect, a method is disclosed for wirelesscommunication by an access node supporting CA of at least a TDD firstcomponent carrier and a FDD second component carrier for a mobiledevice. The method may include receiving, from the mobile device on anUL subframe, control information associated with transmissions on a setof DL subframes including TDD subframes and FDD subframes of therespective first and second component carriers. The method may includedetermining an association between the set of DL subframes and the ULsubframe based on an uplink-downlink configuration of the firstcomponent carrier. The method may include decoding, by the access node,the control information in accordance with the association, wherein eachDL subframe of the FDD second component carrier is associated with an ULsubframe of the first component carrier.

According to another aspect, an access node may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The access node may include means for receiving, from themobile device on an UL subframe, control information associated withtransmissions on a set of DL subframes including TDD subframes and FDDsubframes of the respective first and second component carriers. Theaccess node may include means for determining an association between theset of DL subframes and the UL subframe based on an uplink-downlinkconfiguration of the first component carrier. The access node mayinclude means for decoding, by the access node, the control informationin accordance with the association, wherein each DL subframe of the FDDsecond component carrier is associated with an UL subframe of the firstcomponent carrier.

According to another aspect, an access node may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The access node may include a transceiver configured toreceive, from the mobile device on an UL subframe, control informationassociated with transmissions on a set of DL subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers. The access node may include at least one processor configuredto determine an association between the set of DL subframes and the ULsubframe based on an uplink-downlink configuration of the firstcomponent carrier. The access node may include the at least oneprocessor further configured to decode, by the access node, the controlinformation in accordance with the association, wherein each DL subframeof the FDD second component carrier is associated with an UL subframe ofthe first component carrier. The access node may include a memorycoupled to the at least one processor for storing data.

According to another aspect, a computer program product may include acomputer-readable storage medium including code for causing at least onecomputer to receive, from a mobile device on an UL subframe, controlinformation associated with transmissions on a set of DL subframesincluding TDD subframes and FDD subframes of the respective first andsecond component carriers. The computer-readable storage medium mayinclude code for causing the at least one computer to determine anassociation between the set of DL subframes and the UL subframe based onan uplink-downlink configuration of the first component carrier. Thecomputer-readable storage medium may include code for causing the atleast one computer to decode the control information in accordance withthe association, wherein each DL subframe of the FDD second componentcarrier is associated with an UL subframe of the first componentcarrier.

According to yet another aspect, a method is disclosed for wirelesscommunication by an access node supporting CA of at least a TDD firstcomponent carrier and a FDD second component carrier for a mobiledevice. The method may include determining an association between a DLsubframe of the first component carrier and a set of subframes includingTDD subframes and FDD subframes of the respective first and secondcomponent carriers based on an uplink-downlink configuration of thefirst component carrier. The method may include sending a resource grantto the mobile device in the DL subframe, wherein the resource grantschedules transmission or reception of data by the mobile device withrespect to a subframe in the set of subframes based on the association,and wherein each subframe of the FDD second component carrier isassociated with a DL subframe of the first component carrier.

According to another aspect, an access node may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The access node may include means for determining anassociation between a DL subframe of the first component carrier and aset of subframes including TDD subframes and FDD subframes of therespective first and second component carriers based on anuplink-downlink configuration of the first component carrier. The accessnode may include means for sending a resource grant to the mobile devicein the DL subframe, wherein the resource grant schedules transmission orreception of data by the mobile device with respect to a subframe in theset of subframes based on the association, and wherein each subframe ofthe FDD second component carrier is associated with a DL subframe of thefirst component carrier.

According to another aspect, an access node may be configured for CA ofat least a TDD first component carrier and a FDD second componentcarrier. The access node may include at least one processor configuredto determine an association between a DL subframe of the first componentcarrier and a set of subframes including TDD subframes and FDD subframesof the respective first and second component carriers based on anuplink-downlink configuration of the first component carrier. The accessnode may include at least one processor configured to send a resourcegrant to the mobile device in the DL subframe, wherein the resourcegrant schedules transmission or reception of data by the mobile devicewith respect to a subframe in the set of subframes based on theassociation, and wherein each subframe of the FDD second componentcarrier is associated with a DL subframe of the first component carrier.

According to another aspect, a computer program product may include acomputer-readable storage medium including code for causing at least onecomputer to determine an association between a DL subframe of the firstcomponent carrier and a set of subframes including TDD subframes and FDDsubframes of the respective first and second component carriers based onan uplink-downlink configuration of the first component carrier. Thecomputer-readable storage medium may include code for causing the atleast one computer to send a resource grant to the mobile device in theDL subframe, wherein the resource grant schedules transmission orreception of data by the mobile device with respect to a subframe in theset of subframes based on the association, and wherein each subframe ofthe FDD second component carrier is associated with a DL subframe of thefirst component carrier.

It is understood that other aspects will become readily apparent tothose skilled in the art from the following detailed description,wherein it is shown and described various aspects by way ofillustration. The drawings and detailed description are to be regardedas illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication network, which may be an LTEnetwork or the like.

FIG. 2A shows an exemplary frame structure for a frequency divisionduplex (FDD) carrier in an LTE communication system.

FIG. 2B shows an exemplary frame structure for a time division duplex(TDD) carrier in an LTE communication system.

FIG. 3A shows an example of data transmission on the downlink withhybrid automatic repeat request (HARQ).

FIG. 3B shows an example of data transmission on the uplink with HARQ.

FIG. 4A shows an example of contiguous carrier aggregation.

FIG. 4B shows an example of non-contiguous carrier aggregation.

FIG. 5 shows an exemplary deployment of two component carriers (CCs)with different carrier configurations.

FIG. 6A shows an example of data transmission on the downlink in a firstscenario with an FDD CC controlling a TDD CC using the TDD timeline ofthe scheduled CC.

FIG. 6B shows an example of data transmission on the uplink in a firstscenario with an FDD CC controlling a TDD CC using the TDD timeline ofthe scheduled CC.

FIG. 7A shows an example of data transmission on the downlink in thefirst scenario with an FDD CC controlling a TDD CC using the FDDtimeline of the scheduling CC.

FIG. 7B shows an example of data transmission on the uplink in the firstscenario with an FDD CC controlling a TDD CC using the FDD timeline ofthe scheduling CC.

FIG. 8A shows an example of data transmission on the downlink in asecond scenario with a TDD CC controlling an FDD CC using the FDDtimeline of the scheduled CC.

FIG. 8B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the FDDtimeline of the scheduled CC.

FIG. 9A shows an example of data transmission on the downlink in thesecond scenario with a TDD CC controlling an FDD CC using the TDDtimeline of the scheduling CC.

FIG. 9B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the TDDtimeline of the scheduling CC.

FIG. 10A shows an example of data transmission on the downlink in thesecond scenario with a TDD CC controlling an FDD CC using the hybridtimeline.

FIG. 10B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the hybridtimeline.

FIG. 11 shows an example of a process for sending control information ina wireless network.

FIG. 12 shows an example of a process for receiving control informationin a wireless network.

FIG. 13 shows an example of a process of a mobile device for sendingcontrol information in a wireless network.

FIG. 14 shows an example of a process of a mobile device for identifyingsubframes of aggregated carriers for transmitting or receiving data in awireless network.

FIG. 15 shows an example of a process of an access node for processingcontrol information receiving from a mobile device in a wirelessnetwork.

FIG. 16 shows an example of a process of an access node for sendingcontrol information in a wireless network.

FIG. 17 shows a block diagram of an example base station/eNB and exampleUE, which may be one of the base stations/eNBs and one of the UEs inFIG. 1.

DETAILED DESCRIPTION

Techniques for supporting data transmission in a wireless communicationnetwork with carrier aggregation are disclosed herein. These techniquesmay be used for various wireless communication networks such as CDMA,TDMA, FDMA, OFDMA, SC-FDMA and other wireless networks. The terms“network” and “system” are often used interchangeably. A CDMA networkmay implement a radio technology such as Universal Terrestrial RadioAccess (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA), TimeDivision Synchronous CDMA (TD-SCDMA), and other variants of CDMA.cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network mayimplement a radio technology such as Global System for MobileCommunications (GSM). An OFDMA network may implement a radio technologysuch as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi and Wi-Fi Direct), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®,etc. UTRA and E-UTRA are part of Universal Mobile TelecommunicationSystem (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A),in both frequency division duplexing (FDD) and time division duplexing(TDD), are recent releases of UMTS that use E-UTRA, which employs OFDMAon the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE,LTE-A and GSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). cdma2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thewireless networks and radio technologies mentioned above as well asother wireless networks and radio technologies. For clarity, certainaspects of the techniques are described below for LTE, and LTEterminology is used in much of the description below.

FIG. 1 shows a wireless communication network 100, which may be an LTEnetwork or some other wireless network. Wireless network 100 may includea number of evolved Node Bs (eNBs) 110 and other network entities. AneNB may be an entity that communicates with the UEs and may also bereferred to as a base station, a Node B, an access point, etc. Each eNB110 may provide communication coverage for a particular geographic areaand may support communication for the UEs located within the coveragearea. To improve network capacity, the overall coverage area of an eNBmay be partitioned into multiple (e.g., three) smaller areas. Eachsmaller area may be served by a respective eNB subsystem. In 3GPP, theterm “cell” can refer to a coverage area of an eNB and/or an eNBsubsystem serving this coverage area. In general, an eNB may support oneor multiple (e.g., three) cells. The term “cell” may also refer to acarrier on which an eNB operates.

Wireless network 100 may also include relays. A relay may be an entitythat receives a transmission of data from an upstream entity (e.g., aneNB or a UE) and sends a transmission of the data to a downstream entity(e.g., a UE or an eNB). A relay may also be a UE that relaystransmissions for other UEs.

A network controller 130 may couple to a set of eNBs and may providecoordination and control for these eNBs. Network controller 130 maycommunicate with the eNBs via a backhaul. The eNBs may also communicatewith one another via the backhaul.

UEs 120 may be dispersed throughout the wireless network, and each UEmay be stationary or mobile. A UE may also be referred to as a mobilestation, a terminal, an access terminal, a subscriber unit, a station, anode, etc. A UE may be a cellular phone, a smartphone, a tablet, apersonal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a laptop computer, a cordlessphone, a wireless local loop (WLL) station, a netbook, a smartbook, etc.A UE may be able to communicate with eNBs, relays, other UEs, etc.

Wireless network 100 may utilize FDD and/or TDD. For FDD, the downlinkand uplink may be allocated separate frequency channels. Downlinktransmissions may be sent on one frequency channel, and uplinktransmissions may be sent on another frequency channel. For TDD, thedownlink and uplink may share the same frequency channel, and downlinktransmissions and uplink transmissions may be sent on the same frequencychannel in different time periods.

FIG. 2A shows an exemplary frame structure 200 for FDD in LTE. Thetransmission timeline for each of the downlink and uplink may bepartitioned into units of radio frames. Each radio frame may have apredetermined duration (e.g., 10 milliseconds (ms)) and may bepartitioned into 10 subframes with indices of 0 through 9. Each subframemay include two slots. Each radio frame may thus include 20 slots withindices of 0 through 19. Each slot may include L symbol periods, e.g.,seven symbol periods for a normal cyclic prefix (as shown in FIG. 2A) orsix symbol periods for an extended cyclic prefix. The 2L symbol periodsin each subframe may be assigned indices of 0 through 2L-1. For FDD,each subframe for the frequency channel used for the downlink may bereferred to as a downlink subframe. Each subframe for the frequencychannel used for the uplink may be referred to as an uplink subframe.

A downlink subframe may include a control region and a data region. Thecontrol region may include the first Q symbol periods of the downlinksubframe, where Q may be equal to 1, 2, 3 or 4 and may change fromsubframe to subframe. The data region may include the remaining symbolperiods of the downlink subframe.

FIG. 2B shows an exemplary frame structure 250 for TDD in LTE. Thetransmission timeline for the downlink and uplink may be partitionedinto units of radio frames, and each radio frame may be partitioned into10 subframes with indices of 0 through 9. LTE supports a number ofuplink-downlink configurations for TDD. Subframes 0 and 5 are used forthe downlink and subframe 2 is used for the uplink for alluplink-downlink configurations. Subframes 3, 4, 7, 8 and 9 may each beused for the downlink or uplink depending on the uplink-downlinkconfiguration. Subframe 1 includes three special fields composed of aDownlink Pilot Time Slot (DwPTS) used for downlink control channels aswell as data transmission, a Guard Period (GP) of no transmission, andan Uplink Pilot Time Slot (UpPTS) used for either a random accesschannel (RACH) or sounding reference signals (SRS). Subframe 6 mayinclude only the DwPTS, or all three special fields, or a downlinksubframe depending on the uplink-downlink configuration. The DwPTS, GPand UpPTS may have different durations for different subframeconfigurations. For TDD, each subframe used for the downlink may bereferred to as a downlink subframe, and each subframe used for theuplink may be referred to as an uplink subframe.

Table 1 lists seven exemplary uplink-downlink configurations availablein an LTE network supporting TDD operation. Each uplink-downlinkconfiguration indicates whether each subframe is a downlink subframe(denoted as “D” in Table 1), or an uplink subframe (denoted as “U” inTable 1), or a special subframe (denoted as “S” in Table 1). As shown inTable 1, uplink-downlink configurations 1 through 5 have more downlinksubframes than uplink subframes in each radio frame.

TABLE 1 Uplink-Downlink Configurations for TDD Uplink- Downlink SubframeNumber n Configuration 0 1 2 3 4 5 6 7 8 9 0 D S U U U D S U U U 1 D S UU D D S U U D 2 D S U D D D S U D D 3 D S U U U D D D D D 4 D S U U D DD D D D 5 D S U D D D D D D D 6 D S U U U D S U U D

For both FDD and TDD, a cell may transmit a Physical Downlink ControlChannel (PDCCH), a Physical HARQ Indicator Channel (PHICH), and/or otherphysical channels in the control region of a downlink subframe. ThePDCCH may carry downlink control information (DCI) such as downlinkgrants, uplink grants, etc. The PHICH may carry acknowledgement/negativeacknowledgement (ACK/NAK) feedback for data transmission sent by UEs onthe uplink with hybrid automatic retransmission (HARQ). The cell mayalso transmit a Physical Downlink Shared Channel (PDSCH) and/or otherphysical channels in the data region of a downlink subframe. The PDSCHmay carry data for UEs scheduled for data transmission on the downlinkand/or other information.

For both FDD and TDD, a UE may transmit either a Physical Uplink ControlChannel (PUCCH) in a control region of an uplink subframe or a PhysicalUplink Shared Channel (PUSCH) in a data region of the uplink subframe.The PUCCH may carry uplink control information (UCI) such as channelstate information (CSI), ACK/NAK feedback for data transmission sent tothe UE on the downlink with HARQ, scheduling request, etc. The PUSCH maycarry data and/or UCI.

The various channels in LTE are described in 3GPP TS 36.211, entitled“Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channelsand Modulation,” which is publicly available.

Wireless network 100 may support data transmission with HARQ in order toimprove reliability. For HARQ, a transmitter (e.g., an eNB) may send aninitial transmission of a transport block and may send one or moreadditional transmissions of the transport block, if needed, until thetransport block is decoded correctly by a receiver (e.g., a UE), or themaximum number of transmissions of the transport block has occurred, orsome other termination condition is encountered. A transport block mayalso be referred to as a packet, a codeword, etc. After eachtransmission of the transport block, the receiver may decode allreceived transmissions of the transport block to attempt to recover thetransport block. The receiver may send an ACK if the transport block isdecoded correctly or a NAK if the transport block is decoded in error.The transmitter may send another transmission of the transport block ifa NAK is received and may terminate transmission of the transport blockif an ACK is received.

LTE supports synchronous HARQ on the uplink and asynchronous HARQ on thedownlink. For synchronous HARQ, all transmissions of a transport blockmay be sent in subframes of a single HARQ interlace, which may includeevenly spaced subframes. For asynchronous HARQ, each transmission of atransport block may be sent in any subframe.

A specific HARQ timeline may be used for data transmission with HARQ.The HARQ timeline may indicate a specific subframe in which a grant issent on the PDCCH, a specific subframe in which data transmission issent on the PDSCH or the PUSCH based on the grant, and a specificsubframe in which ACK/NAK for the data transmission is sent on the PUCCHor the PHICH. In general, an HARQ timeline may specify transmission ofcontrol information (e.g., grants, ACK/NAK, etc.), data, and/or otherinformation in a particular sequence and/or at specific times. An HARQtimeline may or may not support retransmission of data. An HARQ timelinemay also be referred to as a scheduling timeline, a data transmissiontimeline, a control timeline, etc.

FIG. 3A shows an example of data transmission on the downlink with HARQ.An eNB may schedule a UE for data transmission on the downlink. The eNBmay send a downlink (DL) grant on the PDCCH and a data transmission ofone or more transport blocks on the PDSCH to the UE in subframe t_(D1).The UE may receive the downlink grant and may process (e.g., demodulateand decode) the data transmission received on the PDSCH based on thedownlink grant. The UE may determine ACK/NAK feedback based on whethereach transport block is decoded correctly or in error. The UE may sendthe ACK/NAK feedback on the PUCCH or PUSCH to the eNB in subframet_(D2). The eNB may receive the ACK/NAK feedback from the UE. The eNBmay terminate transmission of each transport block for which an ACK isreceived and may send another transmission of each transport block forwhich a NAK is received.

FIG. 3B shows an example of data transmission on the uplink with HARQ.An eNB may schedule a UE for data transmission on the uplink. The eNBmay send an uplink (UL) grant on the PDCCH to the UE in subframe t_(U1).The UE may receive the uplink grant and may send a data transmission ofone or more transport blocks on the PUSCH in subframe t_(U2). The eNBmay process (e.g., demodulate and decode) the data transmission receivedon the PUSCH based on the uplink grant. The eNB may determine ACK/NAKfeedback based on whether each transport block is decoded correctly orin error. The eNB may send the ACK/NAK feedback on the PHICH to the UEin subframe t_(U3). The eNB may schedule the UE for data transmission ofeach transport block decoded in error by the eNB (not shown in FIG. 3B).

As shown in FIGS. 3A and 3B, different HARQ timelines may be used fordata transmission on the downlink and uplink. An HARQ timeline used fordata transmission on the downlink may be referred to as a downlink HARQtimeline. An HARQ timeline used for data transmission on the uplink maybe referred to as an uplink HARQ timeline. As shown in FIG. 3A, thedownlink HARQ timeline may indicate (i) a specific downlink subframet_(Dx) in which to send a data transmission on the downlink for adownlink grant sent in a given downlink subframe t_(D1) and (ii) aspecific uplink subframe t_(D2) in which to send ACK/NAK feedback on theuplink for the data transmission in downlink subframe t_(Dx), wheret_(Dx)=t_(D1) when the downlink grant and the downlink data transmissionare sent on the same carrier as shown in FIG. 3A. As shown in FIG. 3B,the uplink HARQ timeline may indicate (i) a specific uplink subframet_(U2) in which to send a data transmission on the uplink for an uplinkgrant sent in a given downlink subframe t_(U1) and (ii) a specificdownlink subframe t_(U3) in which to send ACK/NAK feedback on thedownlink for the data transmission in uplink subframe t_(U2).

Different HARQ timelines may be used for FDD and TDD. Furthermore,different HARQ timelines may be used for different uplink-downlinkconfigurations for TDD and also for different subframes of a givenuplink-downlink configuration.

As shown in FIG. 3A, the downlink HARQ timeline may indicate that for adownlink grant sent in downlink subframe t_(D1), data transmission maybe sent in the same downlink subframe, and ACK/NAK feedback may be sentn_(UL) _(—) _(ACK) subframes later in uplink subframet_(D2)=t_(D1)+n_(UL) _(—) _(ACK). In LTE, n_(UL) _(—) _(ACK)=4 for FDD,and n_(UL) _(—) _(ACK)≧4 for TDD.

As shown in FIG. 3B, the uplink HARQ timeline may indicate that for anuplink grant sent in downlink subframe t_(U1), data transmission may besent n_(UL-Data) subframes later in uplink subframe t_(U2)=t_(U1)+n_(UL)_(—) _(Data), and ACK/NAK feedback may be sent n_(DL) _(—) _(ACK)subframes later in downlink subframe t_(U3)=t_(U2)+n_(DL) _(—) _(ACK).In LTE, n_(UL) _(—) _(Data)=4 and n_(DL) _(—) _(ACK)=4 for FDD, andn_(UL) _(—) _(Data)≧4 and n_(DL) _(—) _(ACK)≧4 for TDD.

For FDD, n_(UL) _(—) _(ACK), n_(UL) _(—) _(Data) and n_(DL) _(—) _(ACK)may each be equal to four. For TDD, n_(UL) _(—) _(ACK), n_(UL) _(—)_(Data), and n_(DL) _(—) _(ACK) may be different for differentuplink-downlink configurations and also for different subframes of agiven uplink-downlink configuration, as described below.

Table 2 lists the value of n_(UL) _(—) _(ACK) for different uplinksubframes t_(D2) in which ACK/NAK may be sent on the PUCCH or PUSCH forthe seven uplink-downlink configurations shown in Table 1. n_(UL) _(—)_(ACK) may be a subframe offset value. For example, for uplink-downlink(UL-DL) configuration 1, subframe 3, the value of 4 may indicateassociation with a subframe that is 4 subframes prior (i.e., subframe 9of the previous radio frame). As an example, for UL-DL configuration 1,ACK/NAK may be sent on the PUCCH or PUSCH (i) in uplink subframe 2 tosupport data transmission on the PDSCH in downlink subframe 5 or 6 ofthe previous radio frame or (ii) in uplink subframe 3 to support datatransmission on the PDSCH in downlink subframe 9 of the previous radioframe.

TABLE 2 n_(UL) _(—) _(ACK) for Downlink HARQ Timeline Uplink- DownlinkDownlink Subframe Number n Configuration 0 1 2 3 4 5 6 7 8 9 0 6 4 6 4 16, 7 4 6, 7 4 2 4, 6, 7, 8 4, 6, 7, 8 3 6, 7, 11 5, 6 4, 5 4 7, 8, 11,12 4, 5, 6, 7 5 4, 5, 6, 7, 8, 9, 11, 12, 13 6 7 7 5 7 7

Table 3 lists the value of n_(UL) _(—) _(Data) for different downlinksubframes t_(U1) in which uplink grants may be sent on the PDCCH for theseven UL-DL configurations shown in Table 1. As an example, for UL-DLconfiguration 1, an uplink grant may be sent on the PDCCH (i) indownlink subframe 1 to support data transmission on the PUSCH in uplinksubframe 7 or (ii) in downlink subframe 4 to support data transmissionon the PUSCH in uplink subframe 8. For UL-DL configurations 1 through 5,more downlink subframes are available to send DCI than uplink subframesavailable to send data. Hence, some downlink subframes are not utilizedto send DCI.

TABLE 3 n_(UL) _(—) _(Data) for Uplink HARQ Timeline Uplink- DownlinkDownlink Subframe Number n Configuration 0 1 2 3 4 5 6 7 8 9 0 4 6 4 6 16 4 6 4 2 4 4 3 4 4 4 4 4 4 5 4 6 7 7 7 7 5

Table 4 lists the value of n_(DL) _(—) _(ACK) for different downlinksubframes t_(U3) in which ACK/NAK may be sent on the PHICH for the sevenUL-DL configurations shown in Table 1. As an example, for UL-DLconfiguration 1, ACK/NAK may be sent on the PHICH (i) in downlinksubframe 1 to support data transmission on the PUSCH in uplink subframe7 of the previous radio frame or (ii) in downlink subframe 4 to supportdata transmission on the PUSCH in uplink subframe 8 of the previousradio frame. A subframe in which ACK/NAK can be sent on the PHICH may bereferred to as a PHICH subframe, a non-zero PHICH subframe, etc. ThePHICH subframes are those with non-zero n_(DL) _(—) _(ACK) values inTable 4.

TABLE 4 n_(DL) _(—) _(ACK) for Uplink HARQ Timeline Uplink- DownlinkDownlink Subframe Number n Configuration 0 1 2 3 4 5 6 7 8 9 0 7 4 7 4 14 6 4 6 2 6 6 3 6 6 6 4 6 6 5 6 6 6 4 7 4 6

Wireless network 100 may support operation on multiple componentcarriers (CCs), which may be referred to as carrier aggregation ormulti-carrier operation. A UE may be configured with multiple CCs forthe downlink and one or more CCs for the uplink for carrier aggregation.For FDD, a CC may comprise one frequency channel for the downlink andanother frequency channel for the uplink. For TDD, a CC may comprise asingle frequency channel used for both the downlink and uplink. A CCconfigured for FDD may be referred to as an FDD CC. A CC configured forTDD may be referred to as a TDD CC. An eNB may transmit data and controlinformation on one or more CCs to a UE. The UE may transmit data andcontrol information on one or more CCs to the eNB.

FIG. 4A shows an example of contiguous carrier aggregation. K CCs may beavailable and may be adjacent to each other, where in general K may beany integer value. K may be limited to 5 or less in some LTE Releases.Each CC may have a bandwidth of up to 20 MHz. The overall systembandwidth may be up to 100 MHz when five CCs are supported. FIG. 4Bshows an example of non-contiguous carrier aggregation. K CCs may beavailable and may be separate from each other. Each CC may have abandwidth of up to 20 MHz.

In LTE Release 10, a UE may be configured with up to five CCs forcarrier aggregation. Each CC may have a bandwidth of up to 20 MHz andmay be backward compatible with LTE Release 8. The UE may thus beconfigured with up to 100 MHz for up to five CCs. In one design, one CCmay be designated as a primary CC (PCC) for the downlink and may bereferred to as a downlink PCC. The downlink PCC may carry certain DCIsuch as downlink grants, uplink grants, ACK/NAK feedback, etc. In onedesign, one CC may be designated as a primary CC for the uplink and maybe referred to as an uplink PCC. The uplink PCC may carry certain UCIsuch as ACK/NAK feedback, etc. In one design, the downlink PCC may bethe same as the uplink PCC, and both may be referred to as a PCC. Inanother design, the downlink PCC may be different from the uplink PCC.

For carrier aggregation, a UE may support operation on one PCC and oneor more secondary CCs (SCCs) on the downlink. The UE may also supportoperation on one PCC and zero or more SCCs on the uplink. An SCC is a CCthat is not a PCC.

Each CC may be associated with a particular CC configuration. A CCconfiguration of a CC may indicate a particular duplexing mode of the CC(e.g., FDD or TDD) and, if TDD, a particular UL-DL configuration of theCC.

LTE Release 10 supports carrier aggregation for multiple CCs with thesame CC configuration. In particular, all CCs for carrier aggregationare configured for either FDD or TDD, and a mixture of FDD and TDD CCsis not allowed. Furthermore, if the CCs are configured for TDD, then allCCs have the same UL-DL configuration, although special subframes may beconfigured separately for different CCs. Restricting all CCs to have thesame FDD or TDD configuration as well as the same UL-DL configurationmay simplify operation.

LTE Release 11 and/or later may support carrier aggregation for multipleCCs with different CC configurations. For example, an aggregation of FDDand TDD CCs may be supported. As another example, an aggregation of CCswith different UL-DL configurations for TDD may be supported. Thedifferent UL-DL configurations for different CCs may be due to variousreasons such as (i) different UL-DL configurations for TDD, e.g., asshown in Table 1, (ii) partitioning of downlink subframes and uplinksubframes to support operation of relays, (iii) allocation of downlinksubframes and uplink subframes to support home eNBs, pico eNBs, etc.,and/or (iv) other reasons. Supporting CCs with different UL-DLconfigurations may provide more flexibility in deployment. Each CC maybe backward compatible with a single CC in LTE Release 8, 9 or 10 in asingle-carrier mode.

FIG. 5 shows an exemplary deployment of two CCs with different CCconfigurations. In this example, CC 1 is configured for FDD and includestwo frequency channels. One frequency channel is for the downlink andincludes downlink subframes, which are denoted as “D” in FIG. 5. Theother frequency channel is for the uplink and includes uplink subframes,which are denoted as “U” in FIG. 5. CC 2 is configured for TDD withUL-DL configuration 1. Subframes 0, 4, 5 and 9 of CC 2 are downlinksubframes, subframes 1 and 6 of CC 2 are special subframes, andremaining subframes 2, 3, 7 and 8 of CC 2 are uplink subframes.

There may be challenges in aggregating multiple CCs with different CCconfigurations. These CCs may be associated with different numbers ofdownlink and uplink subframes. Furthermore, a given subframe t maycorrespond to a downlink subframe on one CC and an uplink subframe onanother CC. Hence, downlink subframes of one or more CCs may overlapwith uplink subframes of one or more other CCs. In general, CCs withdifferent CC configurations may be associated with different sets ofdownlink subframes and uplink subframes. This may complicatetransmission of control information to support data transmission withHARQ.

Carrier aggregation for multiple CCs with different CC configurationsmay be supported with same-carrier control and/or cross-carrier control.For same-carrier control, control information may be sent on a given CCto support data transmission on the same CC. For cross-carrier control,control information may be sent on one CC to support data transmissionon another CC. For both same-carrier control and cross-carrier control,a UE may send control information on the PUCCH on the PCC when notscheduled for data transmission on the uplink.

Carrier aggregation for multiple CCs with different CC configurationsmay also be supported with cross-subframe control. For cross-subframecontrol, control information may be sent in a given subframe and may beapplicable for multiple subframes. For example, multiple grants may besent in a given downlink subframe to schedule data transmission inmultiple downlink subframes and/or multiple uplink subframes.Cross-subframe control may be especially applicable when a CC used tosend grants includes more uplink subframes than downlink subframes.

Table 5 lists two scenarios for carrier aggregation of multiple CCs withdifferent CC configurations. In the first scenario, an FDD CC is a PCC,a TDD CC is an SCC, and the FDD CC controls the TDD CC, e.g., schedulesdata transmission on the TDD CC. In the second scenario, a TDD CC is aPCC, an FDD CC is an SCC, and the TDD CC controls the FDD CC, e.g.,schedules data transmission on the FDD CC. For both scenarios, ascheduling CC is a CC controlling another CC, and a scheduled CC is a CCthat is controlled by another CC.

TABLE 5 Scenario PCC SCC Description First FDD CC TDD CC FDD CC controlsTDD CC scenario FDD CC is scheduling CC, and TDD CC is scheduled CCSecond TDD CC FDD CC TDD CC controls FDD CC scenario TDD CC isscheduling CC, and FDD CC is scheduled CC

For cross-carrier control, data transmission may be supported based onan HARQ timeline of a scheduling CC and/or an HARQ timeline of ascheduled CC. For simplicity, an HARQ timeline of an FDD CC may bereferred to as an FDD timeline, and an HARQ timeline of a TDD CC may bereferred to as a TDD timeline. The HARQ timeline for cross-carriercontrol may be based on one or more of the following:

1. Use HARQ timeline of scheduled CC:

-   -   i) First scenario—use TDD timeline of an UL-DL configuration of        TDD CC when TDD CC is scheduled by FDD CC, or    -   ii) Second scenario—use FDD timeline when FDD CC is scheduled by        TDD CC.

2. Use HARQ timeline of scheduling CC:

-   -   i) First scenario—use FDD timeline when TDD CC is scheduled by        FDD CC, or    -   ii) Second scenario—use TDD timeline of an UL-DL configuration        of TDD CC when FDD CC is scheduled by TDD CC.

3. Use hybrid timeline:

-   -   i) Second scenario—use TDD timeline of an UL-DL configuration of        TDD CC when FDD CC is scheduled by TDD CC, use FDD timeline for        feedback sent on the uplink on FDD CC.

FIG. 6A shows an example of data transmission on the downlink in thefirst scenario with an FDD CC controlling a TDD CC using the TDDtimeline of the scheduled CC. In this case, control information is senton the FDD CC, and downlink data is sent on the TDD CC. FIG. 6A shows anexample in which the TDD CC has UL-DL configuration 1, and data may besent on the TDD CC in only downlink subframes 0, 1, 4, 5, 6 and 9.Downlink grants may be sent on the FDD CC in downlink subframes 0, 1, 4,5, 6 and 9 for downlink data transmission on the TDD CC in downlinksubframes 0, 1, 4, 5, 6 and 9, respectively. ACK/NAK feedback may besent on the FDD CC in uplink subframes 7, 7, 8, 2, 2 and 3 for datatransmission on the TDD CC in downlink subframes 0, 1, 4, 5, 6 and 9,respectively.

FIG. 6B shows an example of data transmission on the uplink in the firstscenario with an FDD CC controlling a TDD CC using the TDD timeline ofthe scheduled CC. In this case, control information is sent on the FDDCC, and uplink data is sent on the TDD CC. FIG. 6B shows an example inwhich the TDD CC has UL-DL configuration 1, and data may be sent on theTDD CC in only uplink subframes 2, 3, 7 and 8. Uplink grants may be senton the FDD CC in downlink subframes 1, 4, 6 and 9 for uplink datatransmission on the TDD CC in uplink subframes 7, 8, 2 and 3,respectively. ACK/NAK feedback may be sent on the FDD CC in downlinksubframes 1, 4, 6 and 9 for data transmission on the TDD CC in uplinksubframes 7, 8, 2 and 3, respectively.

As shown in FIGS. 6A and 6B, when the FDD CC controls the TDD CC usingthe TDD timeline, only applicable subframes of the FDD CC (as determinedby the HARQ timeline of the TDD CC) may be used to send controlinformation on the FDD CC. In particular, uplink and downlink grants maybe sent on the PDCCH and ACK/NAK feedback may be sent on the PHICH indownlink subframes of the FDD CC determined based on the HARQ timelineof the TDD CC. CSI and ACK/NAK feedback may be sent on the PUCCH inuplink subframes of the FDD CC (which may be the PCC) determined basedon the HARQ timeline of the TDD CC. DCI may be sent on the FDD CC basedon DCI formats for TDD.

For uplink data transmission shown in FIG. 6B, PHICH collisions mayoccur, e.g., due to ACK/NAK feedback for data transmission in multipleuplink subframes being mapped to the same downlink subframe of the FDDCC. This may occur due to a given subframe of different CCs beingscheduled in different subframes of the FDD CC. For example, a firstuplink grant may be sent in downlink subframe 3 of the FDD CC toschedule data transmission in uplink subframe 7 of the FDD CC. A seconduplink grant may be sent in downlink subframe 1 of the FDD CC toschedule data transmission in uplink subframe 7 of the TDD CC. TheACK/NAK feedback for data transmission in uplink subframe 7 of both theFDD CC and the TDD CC may be sent on the FDD CC in downlink subframe 1of the next radio frame. PHICH collisions may be handled in similarmanner as in LTE Release 10 carrier aggregation using differentdemodulation reference signals (DMRS). DMRS used in DCIs in downlinksubframe 3 of the FDD CC and downlink subframe 1 of the TDD CC may becoordinated.

FIG. 7A shows an example of data transmission on the downlink in thefirst scenario with an FDD CC controlling a TDD CC using the FDDtimeline of the scheduling CC. FIG. 7A shows an example in which the TDDCC has UL-DL configuration 1, and data may be sent on the TDD CC in onlydownlink subframes 0, 1, 4, 5, 6 and 9. Downlink grants may be sent onthe FDD CC in downlink subframes 0, 1, 4, 5, 6 and 9 for downlink datatransmission on the TDD CC in downlink subframes 0, 1, 4, 5, 6 and 9,respectively. ACK/NAK feedback may be sent on the FDD CC in uplinksubframes 4, 5, 8, 9, 0 and 3 for data transmission on the TDD CC indownlink subframes 0, 1, 4, 5, 6 and 9, respectively.

FIG. 7B shows an example of data transmission on the uplink in the firstscenario with an FDD CC controlling a TDD CC using the FDD timeline ofthe scheduling CC. In this case, control information is sent on the FDDCC, and uplink data is sent on the TDD CC. FIG. 7B shows an example inwhich the TDD CC has UL-DL configuration 1, and data may be sent on theTDD CC in only uplink subframes 2, 3, 7 and 8 1. Uplink grants may besent on the FDD CC in downlink subframes 3, 4, 8 and 9 for uplink datatransmission on the TDD CC in uplink subframes 7, 8, 2 and 3,respectively. ACK/NAK feedback may be sent on the FDD CC in downlinksubframes 1, 2, 6 and 7 for data transmission on the TDD CC in uplinksubframes 7, 8, 2 and 3, respectively.

As shown in FIGS. 7A and 7B, when the FDD CC controls the TDD CC usingthe FDD timeline, only applicable subframes of the FDD CC (as determinedby the HARQ timeline of the FDD CC) may be used to send controlinformation on the FDD CC. In particular, uplink and downlink grants maybe sent on the PDCCH and ACK/NAK feedback may be sent on the PHICH indownlink subframes of the FDD CC determined based on the HARQ timelineof the FDD CC. CSI and ACK/NAK feedback may be sent on the PUCCH inuplink subframes of the FDD CC (which may be the PCC) determined basedon the HARQ timeline of the FDD CC. DCI may be sent on the FDD CC basedon DCI formats for FDD. Search spaces for scheduling the FDD CC and TDDCC may be shared if the same carrier bandwidth and transmission mode areused for both CCs. PHICH collisions may occur as described above and maybe handled in similar manner as in LTE Release 10 carrier aggregationusing different DMRS. PHICH collisions may be readily handled sincegrants can be sent in the same downlink subframe to schedule datatransmission on both the FDD CC and TDD CC.

Using the HARQ timeline of the scheduled/TDD CC in the first scenario(e.g., as shown in FIGS. 6A and 6B) may provide certain advantages. Forexample, resource allocation management for cross-carrier andsame-carrier scheduling of the TDD CC may be easier, and schedulingdecisions for both CCs may be done at the same time.

Using the HARQ timeline of the scheduling/FDD CC in the first scenario(e.g., as shown in FIGS. 7A and 7B) may also provide certain advantages.For example, PHICH collision management for the FDD CC controlling theTDD CC may be performed in similar manner as in LTE Release 10. HARQdelay for the TDD CC may be less due to the use of the FDD timeline(instead of the TDD timeline). Throughput loss due to ACK/NAKbundling/multiplexing may be reduced. Search spaces for scheduling bothCCs may be shared if the same carrier bandwidth and the sametransmission mode are used for both CCs.

In general, when an FDD CC controls a TDD CC in the first scenario, thescheduling FDD CC may follow an FDD timeline or a TDD timeline. Theremay be less scheduling delay, less HARQ delay, and no throughput lossdue to ACK/NAK bundling with cross-carrier control using an FDD timelineversus single-carrier operation on a TDD CC using a TDD timeline. Ifcross-carrier control is not configured and the FDD timeline isconsidered for the PUCCH on the uplink, then a UE may (i) follow the TTDtimeline for scheduling and ACK/NAK feedback on the PHICH and (ii) usethe FDD timeline for feedback on the PUCCH. From a UE complexityperspective, it may be easier to adopt the TDD timeline for thescheduled TDD CC.

For the second scenario, a TDD CC may control an FDD CC. Additionalconsiderations may be needed, regardless of the HARQ timeline selectedfor use, due to lack of uplink and downlink subframes on the TDD CC ascompared to the FDD CC. In one design, only a subset of all downlink anduplink subframes of the FDD CC may be scheduled for data transmissionbased on the selected HARQ timeline, which may be either the FDD or TDDtimeline. In this design, downlink and uplink grants may be sent on thePDCCH, ACK/NAK feedback may be sent on the PHICH, and CSI and ACK/NAKfeedback may be sent on the PUCCH on the TDD CC based on the selectedHARQ timeline. In one design, remaining downlink and uplink subframes ofthe FDD CC may be scheduled based on rules not covered by the selectedHARQ timeline.

FIG. 8A shows an example of data transmission on the downlink in thesecond scenario with a TDD CC controlling an FDD CC using the FDDtimeline of the scheduled CC. In this case, control information is senton the TDD CC, and downlink data is sent on the FDD CC. FIG. 8A shows anexample in which the TDD CC has UL-DL configuration 1 and includes thedownlink and uplink subframes shown in FIG. 8A. Downlink grants may besent on the TDD CC in downlink subframes 0, 1, 4, 5, 6 and 9 fordownlink data transmission on the FDD CC in downlink subframes 0, 1, 4,5, 6 and 9, respectively. ACK/NAK feedback would normally be sent onsubframes 4, 5, 8, 9, 0 and 3 for data transmission on the FDD CC indownlink subframes 0, 1, 4, 5, 6 and 9, respectively. However, onlysubframes 8 and 3 of the TDD CC are uplink subframes, and subframes 4,5, 9 and 0 of the TDD CC are downlink subframes. Hence, ACK/NAK feedbackthat would normally be sent in subframes 4, 5, 9 and 0 based on the FDDtimeline (which are shown by dashed lines with single arrow in FIG. 8A)may be sent in other subframes that are uplink subframes of the TDD CC.

FIG. 8B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the FDDtimeline of the scheduled CC. In this case, control information is senton the TDD CC, and uplink data is sent on the FDD CC. FIG. 8B shows anexample in which the TDD CC has UL-DL configuration 1 and includes thedownlink and uplink subframes shown in FIG. 8B. Uplink grants may besent on the TDD CC in downlink subframes 0, 1, 4, 5, 6 and 9 for uplinkdata transmission on the FDD CC in uplink subframes 4, 5, 8, 9, 0 and 3,respectively. ACK/NAK feedback would normally be sent on the TDD CC insubframes 8, 9, 2, 3, 4 and 7 for data transmission on the FDD CC inuplink subframes 4, 5, 8, 9, 0 and 3, respectively. However, onlysubframes 9 and 4 of the TDD CC are downlink subframes, and subframes 8,2, 3 and 7 of the TDD CC are uplink subframes. Hence, ACK/NAK feedbackthat would normally be sent in subframes 8, 2, 3 and 7 based on the FDDtimeline (which are shown by dashed lines with single arrow in FIG. 8B)may be sent in other subframes that are downlink subframes of the TDDCC.

As shown in FIGS. 8A and 8B, the FDD timeline may be directly applied toa limited number of downlink and uplink subframes of the FDD CC (and noteven on all subframes that overlap with the downlink and uplinksubframes of the TDD CC). The FDD timeline assumes certaindownlink-uplink pair transmissions (e.g., for grants and ACK/NAKfeedback) that may not be available among the overlapping subframes. Newrules may be defined for downlink and uplink subframes of the FDD CC forwhich the FDD timeline cannot be directly applied.

In one design, DCI may be sent on the TDD CC based on DCI formats forFDD. DCI for the FDD CC may be sent in a first search space, and DCI forthe TDD CC may be sent in a second search space. In one design, thesearch spaces for the two CCs are not shared if DCI formats for FDD areused even when the two CCs are associated with the same carrierbandwidth and the same transmission mode.

For uplink data transmission, PHICH collisions may occur due to ACK/NAKfeedback for the FDD CC and the TDD CC being sent in the same downlinksubframe of the TDD CC. PHICH collisions may result from a given uplinksubframe of the two CCs being scheduled from different downlinksubframes of the TDD CC. PHICH collisions may be handled in similarmanner as in LTE Release 10 carrier aggregation using different DMRS.

For downlink data transmission as shown in FIG. 8A, ACK/NAK feedback maybe sent on the PUCCH on the TDD CC based on the FDD timeline for asubset of subframes. The FDD timeline may be applied directly for somedownlink-uplink subframe pairs. ACK/NAK feedback for remaining downlinksubframes of the FDD CC may be handled using techniques such asbundling, multiplexing, etc. Similarly, CSI may be sent in uplinksubframes of the TDD CC based on the FDD timeline/configuration wheneverapplicable and based on other rules otherwise.

FIG. 9A shows an example of data transmission on the downlink in thesecond scenario with a TDD CC controlling an FDD CC using the TDDtimeline of the scheduling CC. In this case, control information is senton the TDD CC, and downlink data is sent on the FDD CC. FIG. 9A shows anexample in which the TDD CC has UL-DL configuration 1 and includes thedownlink and uplink subframes shown in FIG. 9A. Downlink grants may besent on the TDD CC in downlink subframes 0, 1, 4, 5, 6 and 9 fordownlink data transmission on the FDD CC in downlink subframes 0, 1, 4,5, 6 and 9, respectively. ACK/NAK feedback may be sent on the TDD CC insubframes 7, 7, 8, 2, 2 and 3 for data transmission on the FDD CC indownlink subframes 0, 1, 4, 5, 6 and 9, respectively.

FIG. 9B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the TDDtimeline of the scheduling CC. In this case, control information is senton the TDD CC, and uplink data is sent on the FDD CC. FIG. 9B shows anexample in which the TDD CC has UL-DL configuration 1 and includes thedownlink and uplink subframes shown in FIG. 9B. Uplink grants may besent on the TDD CC in downlink subframes 1, 4, 6 and 9 for uplink datatransmission on the FDD CC in uplink subframes 7, 8, 2 and 3,respectively. ACK/NAK feedback may be sent on the TDD CC in subframes 1,4, 6 and 9 for data transmission on the FDD CC in uplink subframes 7, 8,2 and 3, respectively.

As shown in FIGS. 9A and 9B, the TDD timeline may be applied directly todownlink and uplink subframes of the FDD CC that overlap with thedownlink and uplink subframes of the TDD CC. New rules may be defined tosupport data transmission in the remaining downlink and uplink subframesof the FDD CC.

In one design, DCI may be sent on the TDD CC based on DCI formats forTDD. DCI for the FDD CC may be sent in a first search space on the TDDCC, and DCI for the TDD CC may be sent in a second search space on theTDD CC. In one design, the search spaces for the two CCs may be sharedif these two CCs are associated with the same carrier bandwidth and thesame transmission mode.

For uplink data transmission, PHICH collisions may occur and may behandled in similar manner as in LTE Release 10 carrier aggregation usingdifferent DMRS. The FDD CC includes more uplink subframes than the TDDCC, and new rules may be defined for the additional uplink subframes ofthe FDD CC. Some restrictions due to zero-PHICH subframes on the TDD CCmay be defined.

For downlink data transmission as shown in FIG. 9A, ACK/NAK feedback fora subset of the downlink subframes of the FDD CC may be sent in uplinksubframes of the TDD CC based on the TDD timeline. ACK/NAK feedback forthe remaining downlink subframes of the FDD CC may be sent based on newrules, which may include bundling, multiplexing, etc. In some cases(depending on the UL-DL configuration of the TDD CC), the HARQ delay maybe increased if the minimum processing time cannot be met. CSI feedbackfor the FDD CC may be sent in uplink subframes of the TDD CC and mayfollow the TDD timeline/configuration.

Using the HARQ timeline of the scheduled/FDD CC in the second scenario(e.g., as shown in FIGS. 8A and 8B) may provide certain advantages. Forexample, resource allocation management for cross-carrier andsame-carrier scheduling of the FDD CC may be easier, and schedulingdecision may be done at the same time.

Using the HARQ timeline of the scheduling/TDD CC in the second scenario(e.g., as shown in FIGS. 9A and 9B) may also provide certain advantages.For example, search spaces for scheduling both CCs may be shared if bothCCs have the same carrier bandwidth and the same transmission mode.Control rule reuse may be better than when the HARQ timeline is based onthe FDD CC.

In general, when a TDD CC controls an FDD CC in the second scenario,regardless of whether a TDD timeline or an FDD timeline is used,additional rules may be defined in order to cover all downlink anduplink subframes of the FDD CC. Using the TDD timeline for the FDD CCmay provide better reuse of existing rules for TDD operation. Theserules for TDD operation may be applied to downlink and uplink subframesof the FDD CC that overlap with the downlink and uplink subframes of theTDD CC. New rules may be defined for remaining downlink and uplinksubframes of the FDD CC.

The hybrid timeline may be used to schedule an FDD CC with a TDD CC inthe second scenario. In one design of the hybrid timeline, DCI may besent on the TDD CC based on the TDD timeline of the scheduling TDD CC,and UCI may be sent on the FDD CC based on the FDD timeline of thescheduled FDD CC. For data transmission on the downlink, downlink grantsmay be sent on the TDD CC based on the TDD timeline, downlink data maybe sent on the FDD CC as scheduled, and ACK/NAK feedback may be sent onthe FDD CC based on the FDD timeline. UCI may thus be sent on the PUCCHon an uplink CC that is not linked with a downlink PCC, but is insteadlinked with a downlink CC on which data transmission actually occurs.

The hybrid timeline may be implemented in various manners. In onedesign, UCI may be sent on the PUCCH on the FDD CC in all subframes. Inanother design, UCI may be sent on the PUCCH on the FDD CC in only somesubframes, e.g., subframes that cannot be handled by the TDD timeline.

The hybrid timeline may preserve the downlink PCC, which may beimportant for interference management in a heterogeneous network(HetNet). Interference conditions on the uplink may not be impacted inthe same way as the downlink. Hence, UCI may be sent on another uplinkCC with little impact to uplink interference conditions.

FIG. 10A shows an example of data transmission on the downlink in thesecond scenario with a TDD CC controlling an FDD CC using the hybridtimeline. FIG. 10A shows an example in which the TDD CC has UL-DLconfiguration 1 and includes the downlink and uplink subframes shown inFIG. 10A. Downlink grants may be sent on the TDD CC in downlinksubframes 0, 1, 0, 1, 4, 5, 6, 5, 6 and 9 for downlink data transmissionon the FDD CC in downlink subframes 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9,respectively. ACK/NAK feedback may be sent on the FDD CC (instead of theTDD CC) in uplink subframes 4, 5, 6, 7, 8, 9, 0, 1, 2 and 3 for datatransmission on the FDD CC in downlink subframes 0, 1, 2, 3, 4, 5, 6, 7,8 and 9, respectively. If ACK/NAK feedback for downlink datatransmission on the FDD CC is sent in uplink subframes of the TDD CC,then subframe bundling may be utilized, which may result in loss ofdownlink throughput.

The design shown in FIG. 10A attempts to balance the load of the PDCCHacross downlink subframes of the TDD CC, so that at most two downlinkgrants are sent in any given downlink subframe of the TDD CC to scheduleat most two downlink subframes of the FDD CC. Downlink grants may alsobe sent in other manners, e.g., to minimize HARQ delay. For example,downlink subframes 2 and 7 of the FDD CC may be scheduled via downlinkgrants sent in subframes 1 and 6, respectively, of the TDD CC (insteadof in subframes 0 and 5 of the TDD CC as shown in FIG. 10A) in order toreduce HARQ delay. However, this would result in more unbalanced PDCCHload, with one downlink grant being sent in subframe 0 and threedownlink grants being sent in subframe 1 of the TDD CC.

FIG. 10B shows an example of data transmission on the uplink in thesecond scenario with a TDD CC controlling an FDD CC using the hybridtimeline. FIG. 10B shows an example in which the TDD CC has UL-DLconfiguration 1 and includes the downlink and uplink subframes shown inFIG. 10B. Uplink grants may be sent on the TDD CC in downlink subframes0, 0, 1, 4, 4, 5, 5, 6, 9 and 9 for uplink data transmission on the FDDCC in uplink subframes 5, 6, 7, 8, 9, 0, 1, 2, 3 and 4, respectively.ACK/NAK feedback may be sent on the TDD CC in subframes 9, 0, 1, 4, 4,5, 6, 6, 9 and 9 for data transmission on the FDD CC in uplink subframes5, 6, 7, 8, 9, 0, 1, 2, 3 and 4, respectively.

In one embodiment the PUCCH may reside on the TDD CC, with the TDD CCcontrolling a FDD CC. As described above, the PUCCH may carry UCI suchas CSI, ACK/NAK feedback for data transmission sent to the UE on thedownlink with HARQ, scheduling request, etc. Each subframe of the PUCCHmay be used for sending control information related to another subframe.For example, a subframe may be used to send ACK/NAK feedback foracknowledging receipt of data from a preceding subframe. Incross-carrier control, the PUCCH subframes may be used for sendingcontrol information related to a subframe of another carrier.

In a cross-carrier control scheme, an association set of subframes maybe defined that reflects the hybrid timelines. For example, when a TDDCC controls another TDD CC, the UL-DL configurations of the two TDD CCsmay be the same. The association sets may be determined based on static,semi-static, or dynamic rules. In case of static associations, theinformation may be predetermined for each TDD UL-DL configuration. Forexample, the information may be stored (e.g., as a table of values) onthe UE or eNB. For example, the UE or eNB may know of the subframeassociations based on the stored data. For example, the UE or eNB mayuse knowledge of the associations to identify elements of controlinformation associated with particular subframes in the set(s).

Many association sets are possible. For example, some association setsmay associate subframes based on balancing a control load of thecontrolling CC, minimizing HARQ delay between associated subframes, etc.When a TDD CC controls an FDD CC, the subframe configuration between theTDD CC and FDD CC may be different. Modified downlink association setsmay be defined mapping subframes of the TDD CC to the FDD CC. Theassociation sets may include additional DL FDD subframes. Each ULsubframe may be associated with a number (M_(DL)) of DL subframes. TheUL subframes may be associated with TDD subframes and FDD subframes.

The number of elements (M_(DL)) in each set represents a number of DLsubframes associated with a single UL subframe n. The modification fromTable 2 to include DL FDD subframes may be based on designconsiderations such as balancing the load of the PDCCH to provide a moreuniform distribution of the control load across the uplink subframes ofthe TDD CC and/or limiting delay for HARQ feedback. Balancing the loadmay be advantageous where HARQ delay is not a primary consideration orwhere a limited number of bits are available for transmitting controlinformation with a particular uplink control channel format. Forexample, associations which balance or distribute control load may beadvantageously used with PUCCH format 1b. When PUCCH format 3 is used, alarger payload is available, and a load balancing considerations may beless important. Minimizing HARQ delay may be advantageous for caseswhere cross-carrier control with cross-subframe DL scheduling isconfigured. Providing HARQ feedback is subject to a minimum HARQ delayor processing time (e.g., 3 ms in LTE). Minimizing HARQ delay may bedone by associating subframes in the set of DL subframes with a nextavailable UL subframe on the TDD carrier subject to the minimum HARQprocessing time. A scheduling delay may be associated with theprocessing time (temporal) delay.

Table 6 shows association sets based on a design that balances thecontrol load across the UL subframes. Table 6 lists values for differentuplink subframes (e.g., t_(D2) as illustrated in FIG. 3A) in whichACK/NAK may be sent on the PUCCH for the seven UL-DL configurationsshown in Table 1. The values may represent subframe offsets (e.g.,relative to an UL subframe) or other subframe identifiers and theassociation may map a group of downlink subframes, including both TDDsubframes and FDD subframes, with a corresponding UL subframe on thecontrolling TDD carrier for carrying control information. Table 6 may bebased on Table 2, with additional provisions for the FDD subframes. Theadditional values may enable coverage of DL transmissions on eachsubframe in the FDD radio frame. Here, additional values for the FDDsubframes are shown in parentheses “( )”. In the example of Table 6, theadditional elements may be distributed across each UL-DL configurationto provide a uniform distribution. For example, each UL TDD subframe maybe associated with a maximum number of additional elements. In oneaspect, each UL TDD subframe may include at most two additional FDDsubframes. In another example, each UL TDD may be associated with amaximum number of subframes that includes both TDD and FDD subframes. Inanother example, each UL TDD subframe may include at most one moreelement than a standard TDD configuration. For example, for UL-DLconfiguration 1, a TDD CC has six DL and special subframes. Because allsubframes (e.g., ten subframes in a radio frame) of the FDD CC may beused for the DL there are four additional subframes which must beassociated with the UL subframes of the TDD carrier. As an example, forUL-DL configuration 1, ACK/NAK may be sent on the PUCCH (i) in uplinksubframe 2 to support data transmission on the PDSCH in downlinksubframe 5, 6, or 7 of the previous radio frame or (ii) in uplinksubframe 3 to support data transmission on the PDSCH in downlinksubframes 8 or 9 of the previous radio frame.

In the example of Table 6, the association set for each subframe isdesigned to balance the control load on the UL subframes. MinimizingHARQ delay may be a secondary consideration. For example, for UL-DLconfiguration 1, subframes 3 and 8 include two elements while subframes2 and 7 include three elements. Thus for UL-DL configuration 1, each ULsubframe has at most one more element than another DL subframe. Inanother example, UL subframe may include at most two more elements thananother DL subframe.

TABLE 6 Uplink-Downlink Configurations for TDD controlling FDD based ona balanced design UL-DL Config- Subframe Number n uration 0 1 2 3 4 5 67 8 9 0 6 (5), 4, (5), 6 (5) 4, (6) (5) (5) 1 (5), 7, 6 4, (5), 4, (5)7, 6 (5) 2 (5), 8, (5), 7, 4, 6 8, 7, 4, 6 3 7, 6, 6, 5, 5, 4, (10),(10) (10) 11 4 12, 8, 6, 5, 7, (10), 4, 7, 11 (10) 5 13, 12, 9, 8, 7, 5,4, 11, 6, (10) 6 7, (8) (6), 7 5, (5), 7 (5), 7 (6)

Table 7 shows UL-DL configurations for a TDD CC controlling a FDD CCbased on a design that minimizes HARQ delay. Table 7 lists values fordifferent uplink subframes (e.g., t_(D2) of FIG. 3A) in which ACK/NAKmay be sent on the PUCCH for the seven UL-DL configurations shown inTable 1. An association set for Table 7 may be the mapping of eachsubframe to the values. The values may be offsets (e.g., relative to anUL subframe) to preceding subframes. The table of values may be anassociation table. Table 7 may be based on Table 2, with additionalprovisions for FDD subframes. The additional values may enable coverageof DL transmissions on each subframe in the FDD radio frame. Here, theadditional entries are shown in parentheses “( )”. In the example ofTable 7, the additional elements are selected such that each UL TDDsubframe provides HARQ feedback to a closest preceding DL subframe. Inother words, the UL TDD subframe may be a closest succeeding subframefor providing HARQ feedback for the DL subframe(s). As an example, forUL-DL configuration 1, ACK/NAK may be sent on the PUCCH (i) in uplinksubframe 2 to support data transmission on the PDSCH in downlinksubframe 5, 6, 7, or 8 of the previous radio frame or (ii) in uplinksubframe 3 to support data transmission on the PDSCH in downlinksubframe 9 of the previous radio frame. In the example of Table 7, thecontrol load of the PUCCH for each subframe is designed so as tominimize HARQ delay. Balancing the control load across the UL subframesmay be a secondary consideration. For example, the association sets inTable 7 may include shorter HARQ delays than the association sets inTable 6, which may be based on a design that balances the control load.For example, comparing UL-DL configuration 1 of Table 7 with Table 6,Table 7 DL subframes 2 and 7 include delays of 5 subframes and also someshorter delays of 4 subframes for the additional FDD CC subframes,whereas Table 6 includes delays of 5 subframes for the additional FDD CCsubframes. As the example illustrates, Table 7 may provide shorter HARQfeedback delays for some DL subframes. On the other hand, the subframesin Table 6 may be more balanced compared to Table 7, and Table 6 mayinclude more equal numbers of elements spread across the UL subframesfor each UL-DL configuration.

TABLE 7 Uplink-Downlink Configurations for TDD controlling FDD based ona design that minimizes HARQ delay UL-DL Config- U Subframe Number nuration 0 1 2 3 4 5 6 7 8 9 0 (5), 6 (4), 4 (4), 4, (5) (5), 6 (5) 1(4), 4 (4), 4 (5), 7, 6 (5), 7, 6 2 (5), 8, (5), 7, 4, 6 8, 7, 4, 6 3 7,6, 6, 5, 5, 4, (10), (10) (10) 11 4 12, 8, 6, 5, 7, (10), 4, 7, 11 (10)5 13, 12, 9, 8, 7, 5, 4, 11, 6, (10) 6 (4), 7 5 (4), (4), 7 (5), 7 (5),7

In LTE where PUCCH format 1b with channel selection is used, there maybe a unique M_(DL) across all CCs within a subframe. In anotherembodiment, CCs may have different M_(DL) within one subframe. Forexample, for a TDD CC of configuration 1, M_(DL)=2, whereas for an FDDCC, M_(DL)=3. The association sets may need to take into accountcombinations of different M_(DL).

In the case of the balanced design, M_(DL) for the FDD CC (M_(FDD)) andM_(DL) for the TDD CC (M_(TDD)) may be selected such that the load isbalanced across the UL subframes. In one aspect, the association setsfor the balanced design may be selected to limit the M_(FDD) to equalthe M_(TDD) plus one additional element such that M_(TDD)=M_(DL) andM_(FDD)=M_(DL)+1.

In LTE Rel-10, a broadcast parameter n_(PUCCH,i) ⁽¹⁾ may define a numberof resources reserved for PUCCH format 1b resources. n_(PUCCH,i) ⁽¹⁾ maybe determined based on a number of the first control channel elements(CCE) used for transmission of the corresponding PDCCH on the primarycell (e.g., the TDD CC). If cross-carrier control is not configured, thevalues n_(PUCCH,2) ⁽¹⁾ and n_(PUCCH,3) ⁽¹⁾ may be determined accordingto a higher layer configuration. A transmit power control (TPC) field inthe DCI format of the corresponding PDCCH may be used to determine thePUCCH resource values from one of the four resource values configured bythe higher layers.

In one aspect, the modified association table for M_(TDD)=M_(DL) andM_(FDD)=M_(DL)+1 may be based on existing TDD multiplexing tablescorresponding to the value M_(FDD), where entry for the PCC (e.g., theTDD CC) is modified to reflect M_(FDD). A new table for M_(FDD)=5 mayneed to be established, or alternatively, support for M_(FDD)=5 may notbe supported in case carrier aggregation of FDD CC and TDD CC when thePUCCH is configured on the TDD CC.

In another aspect, the modified association table may be based onexisting TDD multiplexing tables corresponding to the value M_(TDD),where entries for the SCC (e.g., the FDD CC) is modified to reflectM_(TDD). Additional entries corresponding to the additional FDDsubframes may first be bundled/multiplexed with one of the existingentries, and sent on the UL subframe. The bundled/multiplexed data maybe sent in an uplink control format of the TDD carrier.

In the case of using PUCCH format 3, LTE Rel-10 methods may be reusedfor aggregation of FDD CC and TDD CC where the number of bits for eachcell in a subframe may be different. For example, LTE Rel-10 specifiesthat a UE may determine the number of HARQ bits associated with an ULsubframe n based on the number of configured serving cells, the downlinktransmission modes configured for each serving cell and M_(DL) which isthe number of elements in a set K. A value (O_(ACK)) may be defined asthe number of HARQ bits for each serving cell, and it may be determinedon the M_(TDD) for the TDD CC and M_(FDD) for the FDD CC. If the numberof feedback bits is larger than 20, spatial ACK/NACK bundling of codewords within a DL subframe may be performed for each CC, as in LTERel-10. In the case where feedback is larger than 20, even after spatialbundling (e.g., 5 CCs with M_(FDD)>4) additional rules may be used. Forexample, bits may be bundled across subframes of the FDD CC withM_(FDD)>4.

For cross-carrier control with the TDD CC controlling the FDD CC, onlyDL and special subframes on the TDD CC may be used for assignments andgrants. In contrast, for the FDD CC controlling the TDD CC, allsubframes on the FDD CC may be available for scheduling. Using the TDDCC to control the FDD CC may present challenges because the FDD CCincludes more subframes than the TDD CC. Two possible approaches arediscussed below for granting resources when the TDD CC controls the FDDCC.

In one embodiment, only a subset of subframes on the FDD CC may bescheduled. For example, only those subframes on the DL or UL of the FDDCC that correspond to the DL or UL of the TDD CC may be scheduled. Inthis embodiment, the unscheduled subframes may be wasted as the UE doesnot use the unscheduled subframes. If the subframes are notcross-scheduled from the TDD CC, however, the UE may still be able touse the subframes.

In another embodiment, all subframes on the DL or UL of the FDD CC maybe scheduled. The scheduling may be based on cross-subframe control ormulti-transmission time interval scheduling. Scheduling of the set ofsubframes through cross-subframe control from a specific subframe may bestatic, semi-static, or dynamic. In case of static scheduling, theinformation may be predetermined for each TDD UL-DL configuration. Forexample, the information may be stored (e.g., as a table of values) onthe UE or eNB. For example, the UE or eNB may know of the subframeassociations based on the stored data. For example, the UE or eNB mayuse knowledge of the associations to identify elements of controlinformation associated with particular subframes in the set(s). In thecase of semi-static scheduling, the configuration may be specified byRRC configuration. For example, the UE may receive RRC configurationmessages (e.g., periodically, at predetermined time periods, etc.) touse a particular association set. In the case of dynamic scheduling, theinformation may be provided by a cross-subframe indicator (e.g., via theeNB) to the UE. The dynamic scheduling may be a combination of static orsemi-static configurations. The scheduling may be bounded by allowing atleast three ms processing time by the UE. DL assignments may betransmitted in the same subframe as the associated DL subframe. In otherwords, for DL assignments, the offset between the assigning DL subframeand associated DL subframe may be zero.

A static configuration may be defined for each TDD UL-DL configuration.On the UL scheduling, in an example, for TDD UL-DL configurations 1-6(see Table 1) and normal HARQ operation, when a UE detects the PDCCHwith DCI format 0 and/or a PHICH transmission in a subframe n intendedfor the UE, the UE may adjust the corresponding PUSCH transmission insubframe n+k, with k defined by the association table.

Table 8 shows a set of configurations covering all possible resourcegrants for UL subframes in a radio frame. A resource grant may be anuplink grant or a downlink assignment. An association set for Table 8may be the mapping of each subframe (e.g., t_(U1) of FIG. 3B) to thevalues. The values may be offsets to succeeding subframes. The table ofvalues may be an association table. As an example, for UL-DLconfiguration 1, UL resource grants may be sent on the PDCCH (i) indownlink subframe 0 to grant UL resources for subframes 4, 5, or 6 ofthe current radio frame or (ii) in downlink subframe 1 to grant ULresources for subframes 5, 6, or 7 of the current radio frame. It may benoted that the example for the subframes 0 and 1 show redundant ULresources grants for subframes 5 and 6. Only a subset of the possible ULsubframe configurations needs to be configured or specified for eachUL-DL TDD CC configuration. Table 9 below shows one exampleconfiguration based on the set of possible configurations of Table 8.

TABLE 8 Set of configurations covering all possible grants for ULsubframes in a radio frame UL-DL Subframe Number n Configuration 0 1 2 34 5 6 7 8 9 0 4, 5, 6 4, 4, 5, 6 4, 5, 6 5, 6 1 4, 5, 6 4, 4, 5, 4, 5, 64, 5, 6 4, 5, 5, 6 6, 7 6, 7 2 4, 5, 6 4, 4, 5, 4, 5, 4, 5, 6 4, 5, 7 4,5, 4, 5, 5, 6 6, 7 6, 7 6, 7 6, 7 3 4, 5, 4, 4, 5, 6 4, 5 4 4, 7 4, 6, 76, 7 5, 6, 7 4 4, 5, 4, 4, 5, 4, 5, 6 4, 5 4, 7 4, 6, 7 4, 5, 6, 7 5, 6,7 6, 7 6, 7 5 4, 5, 4, 4, 5 4, 5, 4, 5, 6 4, 5, 7 4, 6, 7 4, 5, 4, 5, 6,7 5, 6, 7 6, 7 6, 7 6, 7 6, 7 6 5, 6, 7 4, 5, 7 4, 5, 4, 5, 7 5, 6, 7 6,7

Table 9 shows one configuration from all the possible configurations ofTable 8 to cover all UL subframes in a radio frame. An association setfor Table 9 may be the mapping of each subframe (e.g., t_(U1) of FIG.3B) to the values. The values may be offsets to succeeding subframes.The table of values may be an association table. As an example, forUL-DL configuration 1, UL resource grants may be sent on the PDCCH (i)in downlink subframe 0 to grant UL resources for subframes 4 or 5 of thecurrent radio frame or (ii) in downlink subframe 1 to grant UL resourcesfor subframes 6 or 7 of the current radio frame. In the example of Table9, the resource grant load of the PDCCH for each subframe is designed soas to balance the resource grant load. For example, for UL-DLconfiguration 1, subframes 0, 1, 5, and 6 include 2 resource grantswhile subframes 4 and 9 include one resource grant. Thus for UL-DLconfiguration 1, each subframe has at most one more resource grant thananother DL subframe. In another example, each subframe may include atmost two more resource grants than another DL subframe. In thisinstance, the design balances the grant load across the DL subframes.

TABLE 9 One example configuration to cover UL subframes in a radio framebased on a configuration to balance resource grant load UL-DL Config-Subframe Number n uration 0 1 2 3 4 5 6 7 8 9 0 4, 5 5, 6 4, 5 5, 6 1 4,5 5, 6 4 4, 5 5, 6 4 2 4 4, 5 4 4 4 4, 5 4 4 3 4, 6 6, 7 4 4 4 4 4, 6 44, 5 5, 6 4 4 4 4 4 4 5 4 4, 5 4 4 4 4 4 4 4 6 5, 7 5, 7 4, 7 4, 5, 7 5

Table 10 shows one configuration to cover all UL subframes in a radioframe. As association set for Table 10 may be the mapping of eachsubframe (e.g., t_(U1) of FIG. 3B) to the values. The values may beoffsets to succeeding subframes. The table of values may be anassociation table. As an example, for UL-DL configuration 1, UL resourcegrants may be sent on the PDCCH (i) in downlink subframe 0 to grant ULresources for subframe 4 of the current radio frame or (ii) in downlinksubframe 1 to grant UL resources for subframes 5, 6, or 7 of the currentradio frame. In the example of Table 10, the resource grant load of thePDCCH for each subframe is designed so as to minimize the schedulingdelay. For example, comparing UL-DL configuration 1 of Table 10 withTable 9, Table 10 downlink subframes include shorter delays of 4(subframe 0) and 4, 5, 6 (subframe 1), whereas Table 10 includes longerdelays of 4, 5 (subframe 0) and 5, 6 (subframe 1). On the other hand,the subframes in Table 9 are more balanced with a more equal number ofelements spread across the subframes.

TABLE 10 One example configuration to cover UL subframes in a radioframe based on a configuration to minimize scheduling delay UL-DLSubframe Number n Configuration 0 1 2 3 4 5 6 7 8 9 0 4 4, 4 4, 5, 6 5,6 1 4 4, 4 4 4, 5, 6 4 5, 6 2 4 4, 5 4 4 4 4, 5 4 4 3 4 4, 4 4 4 4 4 5,6, 7 4 4 4, 4 4 4 4 4 4 5, 6 5 4 4, 5 4 4 4 4 4 4 4 6 4 4, 4 4, 5, 6 45, 6, 7

For DL scheduling, the overlapping DL subframes of the scheduled CC andscheduling CC may follow rules from LTE Rel-8/9/10. In cases where thescheduling CC has an UL subframe and the scheduled CC has a DL subframe,cross-subframe scheduling may be utilized.

Table 11 shows a set of configurations to cover all possible assignmentsor grants for DL subframes in a radio frame. An association set forTable 11 may be the mapping of each subframe (e.g., t_(D1) of FIG. 3A)to the values. The values may be offsets to succeeding subframes. For DLassignments, the assignment may be transmitted in the same subframe asthe data such that the offset may be zero. The table of values may be anassociation table. As an example, for UL-DL configuration 1, DL resourcegrants may be sent on the PDCCH (i) in downlink subframe 0 to grant DLresources for subframes 0 or 2 of the current radio frame or (ii) indownlink subframe 1 to grant UL resources for subframes 1, 2, or 3 ofthe current radio frame. It may be noted that the example for thesubframes 0 and 1 show redundant DL assignments for subframe 2. Only asubset of the possible DL subframe configurations may need to beconfigured or specified for each UL-DL TDD CC configuration. Table 12below shows one example configuration.

TABLE 11 Set of configurations covering all possible assignments for DLsubframes in a radio frame UL-DL Config- Subframe Number n uration 0 1 23 4 5 6 7 8 9 0 0, 2, 3 0, 0, 2, 3 0, 1, 1, 2, 3 2, 3 1 0, 2 0, 0 0, 20, 1, 2 0 1, 2 2 0, 2 0, 1 0 0 0 0, 1 0 0 3 0, 2, 3 0, 0 0 0 0 0 1, 2, 34 0, 2 0, 0 0 0 0 0 0 1, 2 5 0, 2 0, 1 0 0 0 0 0 0 0 6 0, 2, 3 0, 0, 20, 1, 2 0 1, 2, 3

Table 12 shows one configuration from all the possible configurations ofTable 11 to cover all DL subframes in a radio frame. An association setfor Table 12 may be the mapping of each subframe (e.g., t_(D1) of FIG.3A) to the values/elements. The values may be offsets to succeedingsubframes.

In the example of Table 12, the elements are distributed across eachUL-DL configuration to provide a uniform distribution. Minimizingscheduling delay may be a secondary consideration. For example, each DLTDD subframe may include a maximum number of additional elements. In oneaspect, each DL TDD subframe may include at most two additionalelements. In another example, each DL TDD may include a maximum numberof total elements. In another example, each DL TDD subframe may includeat most two more elements than another DL TDD subframe in the same UL-DLconfiguration.

As an example, for UL-DL configuration 1, DL assignments may be sent onthe PDCCH (i) in downlink subframe 0 to assign DL resources forsubframes 0 or 2 of the current radio frame or (ii) in downlink subframe1 to assign DL resources for subframes 1 or 3 of the current radioframe. In the example of Table 12, the DL assignment load of the PDCCHfor each subframe is designed so as to balance the assignment load. Forexample, for UL-DL configuration 1, subframes 0, 1, 5, and 6 include 2resource grants while subframes 4 and 9 include one resource grant. Thusfor UL-DL configuration 1, each subframe has at most one more resourcegrant than another DL subframe. In one aspect, the resource grant orassignment load for UL-DL configurations 0-6 may be balanced such thateach subframe has at most two more resource grants than another DLsubframe.

TABLE 12 One example configuration to cover DL subframes in a radioframe based on a configuration to balance assignment load UL-DL SubframeNumber n Configuration 0 1 2 3 4 5 6 7 8 9 0 0, 2 0, 0, 2 0, 2, 2, 3 3 10, 2 0, 2 0 0, 2 0, 2 0 2 0 0, 1 0 0 0 0, 1 0 0 3 0, 2 0, 0 0 0 0 0 2, 34 0, 2 0, 2 0 0 0 0 0 0 5 0 0, 1 0 0 0 0 0 0 0 6 0, 2 0, 0, 2 0, 2 0 2,3

Table 13 shows one configuration from all the possible configurations ofTable 11 to cover all DL subframes in a radio frame. An association setfor Table 13 may be the mapping of each subframe (e.g., t_(D1) of FIG.3A) to the values. The values may be offsets to succeeding subframes. Asan example, for UL-DL configuration 1, DL assignments may be sent on thePDCCH (i) in downlink subframe 0 to assign DL resources for subframe 4of the current radio frame or (ii) in downlink subframe 1 to assign DLresources for subframes 5, 6, or 7 of the current radio frame. In theexample of Table 13, the assignment load of the PDCCH for each subframeis designed so as to minimize the scheduling delay.

TABLE 13 One example configuration to cover DL subframes in a radioframe based on a configuration to minimize scheduling delay UL-DLSubframe Number n Configuration 0 1 2 3 4 5 6 7 8 9 0 0 0, 0 0, 1, 1, 2,3 2, 3 1 0 0, 0 0 0, 1, 2 0 1, 2 2 0 0, 1 0 0 0 0, 1 0 0 3 0 0, 0 0 0 00 1, 2, 3 4 0 0, 0 0 0 0 0 0 1, 2 5 0 0, 1 0 0 0 0 0 0 0 6 0 0, 0 0, 1,2 0 1, 2, 3

Tables may define possible cross-subframe scheduling of each subframefrom a TDD CC. RRC protocol configuration data may define an applicableoffset (k) for each UE and cross-scheduling CC. In one example, theconfiguration may be provided based on the scheduling TDD CC UL-DLconfiguration and defined for cross-scheduling of all subframes (e.g.,as if the cross-scheduled CC were an FDD CC). The configuration for across-scheduled TDD CC may be derived implicitly for each UL-DL TDD CCconfiguration, taking into account only applicable subframes, as thesubset of the configuration for FDD CC cross-scheduling.

The same configuration may be used for a group of cross-scheduled CCs.For example, all cross-scheduled FDD CCs may use the same configuration.For example, all cross-scheduled TDD CCs of the same UL-DL configurationmay use the same given configuration.

In another embodiment, configuration may be given per eachcross-scheduled CC configuration. Cross scheduled CCs may be different,e.g., FDD CC and a TDD CC, and possibly of different TDD UL-DLconfigurations and may have different scheduling requirements. Forexample, not all subframes may need to be scheduled on all SCCs.

In a semi-static configuration, RRC protocol configuration data mayallow cross scheduling of a subframe from a single subframe only. Thisapproach may be similar to that used for LTE Rel-10 for cross-carrierscheduling. Cross-scheduling of a subframe from multiple subframes maybe enabled by RRC protocol configuration data, which may offer morescheduling flexibility. Distribution of the PDCCH load in case controlspace is crowded.

In one example, RRC configuration data may be used to select a subsetfrom the set of all possible configurations. For example, for TDD UL-DLconfiguration 1 the subset to be used may be configured by RRCconfiguration data.

In another embodiment, dynamic cross-subframe schedule may be utilizedas follows. Dynamic cross-scheduling may be utilized in conjunction withsemi-static and/or static configurations. Dynamic scheduling may beperformed based on configuration such as where a UE may becross-scheduled on a subframe only from particular subframe(s) ofparticular CC(s). For example, each subframe may schedule up to 2 othersubframes. Dynamic cross-scheduling may be based on all possiblecross-subframe scheduling options for a specific TDD UL-DL configurationof the scheduling CC. This may provide the most flexibility; however,overhead for signaling may be increased.

Dynamic scheduling may configure non-overlapping UE-specific searchspaces for cross-subframe scheduling. A search space may be designatedfor each subframe that may not be shared for scheduling of differentsubframes. This method may be less efficient in terms of the searchspace utilization. No additional overhead for DCI for subframeindication may be needed. However, this may be difficult. Dynamicscheduling may utilize various resource allowance sizes. Additionalbit(s) in the DCI format may be needed to cover the maximum number ofsubframes that may be scheduled from one subframe. For example, threesubframes may be scheduled in the UL and six in the DL, not includingthe scheduling DL subframe itself. In this case, two bits for the threeUL subframes, and three bits for the six DL subframes may be needed.Limiting the maximum number of subframes that may be scheduled from onesubframe may reduce the overhead. For example, a rule may limit thescheduling to two other subframes. If a subframe schedulingcorrespondence is defined such that up to two UL subframes may bescheduled from a DL subframe, the number of bits is reduced to one bitfor UL scheduling. The configuration (e.g., table) may specify which twosubframes may be scheduled. The information may be embedded in a carrierindication field (CIF). For example, the CIF may include three bits,with two bits (e.g., supporting four carriers) used for carrierindication and one bit (e.g., supporting two subframes) for subframeindication.

FIG. 17 shows a block diagram of an example base station/eNB 110 y andan example UE 120 y, which may be one of the base stations/eNBs and oneof the UEs in FIG. 1. Base station 110 y may be equipped with T antennas1734 a through 1734 t, and UE 120 y may be equipped with R antennas 1752a through 1752 r, where in general T≧1 and R≧1.

At base station 110 y, a transmit processor 1720 may receive data from adata source 1712 for one or more UEs, process (e.g., encode andmodulate) the data for each UE based on one or more modulation andcoding schemes selected for that UE, and provide data symbols for allUEs. Transmit processor 1720 may also process control information (e.g.,for downlink grants, uplink grants, ACK/NAK feedback, etc.) and providecontrol symbols. Processor 1720 may also generate reference symbols forreference signals. A transmit (TX) multiple-input multiple-output (MIMO)processor 1730 may precode the data symbols, the control symbols, and/orthe reference symbols (if applicable) and may provide T output symbolstreams to T modulators (MOD) 1732 a through 1732 t. Each modulator 1732may process its output symbol stream (e.g., for OFDM, etc.) to obtain anoutput sample stream. Each modulator 1732 may further condition (e.g.,convert to analog, amplify, filter, and upconvert) its output samplestream to obtain a downlink signal. T downlink signals from modulators1732 a through 1732 t may be transmitted via T antennas 1734 a through1734 t, respectively.

At UE 120 y, antennas 1752 a through 1752 r may receive the downlinksignals from base station 110 y and/or other base stations and mayprovide received signals to demodulators (DEMODs) 1754 a through 1754 r,respectively. Each demodulator 1754 may condition (e.g., filter,amplify, downconvert, and digitize) its received signal to obtain inputsamples. Each demodulator 1754 may further process the input samples(e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 1756may obtain received symbols from all R demodulators 1754 a through 1754r, perform MIMO detection on the received symbols, and provide detectedsymbols. A receive processor 1758 may process (e.g., demodulate anddecode) the detected symbols, provide decoded data for UE 120 y to adata sink 1760, and provide decoded control information to acontroller/processor 1780. A channel processor 1784 may measure thechannel response and interference for different carriers based onreference signals received on these carriers and may determine CSI foreach carrier of interest.

On the uplink, at UE 120 y, a transmit processor 1764 may receive andprocess data from a data source 1762 and control information (e.g.,ACK/NAK feedback, CSI, etc.) from controller/processor 1780. Processor1764 may also generate reference symbols for one or more referencesignals. The symbols from transmit processor 1764 may be precoded by aTX MIMO processor 1766 if applicable, further processed by modulators1754 a through 1754 r (e.g., for SC-FDM, OFDM, etc.), and transmitted tobase station 110 y. At base station 110 y, the uplink signals from UE120 y and other UEs may be received by antennas 1734, processed bydemodulators 1732, detected by a MIMO detector 1736 if applicable, andfurther processed by a receive processor 1738 to obtain decoded data andcontrol information sent by UE 120 y and other UEs. Processor 1738 mayprovide the decoded data to a data sink 1739 and the decoded controlinformation to controller/processor 1740.

Controllers/processors 1740 and 1780 may direct the operation at basestation 110 y and UE 120 y, respectively. Processor 1740 and/or otherprocessors and modules at base station 110 y may perform or directprocess 1100 in FIG. 11, process 1500 in FIG. 15, process 1600 in FIG.16, and/or other processes for the techniques described herein.Processor 1780 and/or other processors and modules at UE 120 y mayperform or direct process 1200 in FIG. 12, process 1300 in FIG. 13,process 1400 in FIG. 14, and/or other processes for the techniquesdescribed herein. Memories 1742 and 1782 may store data and programcodes for base station 110 y and UE 120 y, respectively. A scheduler1744 may schedule UEs for data transmission on the downlink and/oruplink.

FIG. 11 shows an example of a process 1100 for sending controlinformation in a wireless network. Process 1100 may be performed by abase station (e.g., an eNB), as described below, or by a similar networkentity. The base station may determine first and second CCs configuredfor a UE, with the first and second CCs being associated with differentCC configurations (block 1112). In one design, the different CCconfigurations may correspond to a combination of FDD and TDD. One CCmay be associated with FDD, and the other CC may be associated with TDD.In another design, the different CC configurations may correspond todifferent UL-DL configurations of the first and second CCs for TDD. TheCC configurations of the two CCs may also be different in other manners.The base station may send control information on the first CC to supportdata transmission on the second CC based on a first HARQ timeline forthe first CC and/or a second HARQ timeline for the second CC (block1114).

In the first scenario described above, the first CC may be associatedwith FDD, and the second CC may be associated with TDD. The first/FDD CCmay control the second/TDD CC. In one design, the HARQ timeline of thescheduled CC (or the TDD timeline) may be utilized, e.g., as shown inFIGS. 6A and 6B. In this design, for block 1114, the base station maysend the control information on the first CC based on the second HARQtimeline for an UL-DL configuration of the second CC for TDD. In anotherdesign, the HARQ timeline of the scheduling CC (or the FDD timeline) maybe utilized, e.g., as shown in FIGS. 7A and 7B. In this design, forblock 1114, the base station may send the control information on thefirst CC based on the first HARQ timeline for the first CC. For bothdesigns, data transmission may be scheduled on the second CC based onthe first or second HARQ timeline only in downlink and uplink subframesof the second CC matching downlink and uplink subframes of the first CC.Data transmission in remaining subframes may be scheduled based on otherrules.

In the second scenario described above, the first CC may be associatedwith TDD, and the second CC may be associated with FDD. The first/TDD CCmay control the second/FDD CC. In one design, the HARQ timeline of thescheduled CC (or the FDD timeline) may be utilized, e.g., as shown inFIGS. 8A and 8B. In this design, for block 1114, the base station maysend the control information on the first CC based on the second HARQtimeline for the second CC. In another design, the HARQ timeline of thescheduling CC (or the TDD timeline) may be utilized, e.g., as shown inFIGS. 9A and 9B. In this design, for block 1114, the base station maysend the control information on the first CC based on the first HARQtimeline for an uplink-downlink configuration of the first CC for TDD.

In another design, a hybrid timeline may be utilized, e.g., as shown inFIG. 10A or 10B. The first/TDD CC may control the second/FDD CC, e.g.,as shown in FIG. 10A. The base station may send DCI on the first CCbased on the first HARQ timeline for the first CC. The base station mayreceive UCI sent on the second CC based on the second HARQ timeline ofthe second CC.

FIG. 12 shows an example of a process 1200 for receiving controlinformation in a wireless network. Process 1200 may be performed by aUE, as described above, or by a similar mobile entity or device. The UEmay determine first and second CCs configured for the UE, with the firstand second CCs being associated with different CC configurations (block1212). The UE may receive control information sent on the first CC tosupport data transmission on the second CC, with the control informationbeing sent based on a first HARQ timeline for the first CC and/or asecond HARQ timeline for the second CC (block 1214).

FIG. 13 shows an example of a process 1300 for sending controlinformation in a wireless network. Process 1300 may be performed by amobile device (e.g., a UE), as described above, or by a similar mobileentity or device. The mobile device may determine an association betweena set of DL subframes including TDD subframes and FDD subframes of therespective first and second component carriers and a UL subframe of thefirst component carrier based on an uplink-downlink configuration of thefirst component carrier (block 1302). In one example, block 1302 may beperformed by processor 1708, or processor 1708 coupled to memory 1782.The association, for example, may provide a mapping between the set ofDL subframes and the UL subframe of the first component carrier. Theassociation may be stored (e.g., as a table of values, as a functionthat calculates the values, etc.) on a memory of the mobile device. Theassociation may be based on subframe offsets.

In one design, the mobile device may generate control informationassociated with transmissions on the set of DL subframes (block 1304).In one example, block 1304 may be performed by processor 1708, orprocessor 1708 coupled to memory 1782.

In one design, the mobile device may send the control information on theUL subframe of the first component carrier based on the association,wherein each DL subframe of the FDD second component carrier isassociated with a corresponding UL subframe of the first componentcarrier (block 1306). In one example, block 1306 may be performed by anycombination of antennas 1752, modulators 1754, processors 1708, 1764,1766, and/or memory 1782, 1762. The control information may bedistributed on the UL subframes to balance the load on the UL subframes.The control information may be sent on UL subframes that minimizes orlimits a HARQ delay subject to a minimum three ms processing time by themobile device. The control information may be bundled for transmissionon the UL subframes.

FIG. 14 shows an example of a process 1400 for identifying subframes ofaggregated carriers for transmitting or receiving data in a wirelessnetwork. Process 1400 may be performed by a mobile device (e.g., a UE),as described above, or by some other entity. The mobile device mayreceive a resource grant in a DL subframe of the first component carrier(block 1402). In one example, block 1402 may be performed by anycombination of antennas 1752, demodulators 1754, detector 1756,processors 1758, 1780, and/or memory 1760, 1782.

In one design, the mobile device may determine an association betweenthe DL subframe and a set of subframes including TDD subframes and FDDsubframes of the respective first and second component carriers based onan uplink-downlink configuration of the first component carrier (block1404). In one example, block 1404 may be performed by processor 1708, orprocessor 1708 coupled to memory 1782.

In one design, the mobile device may identify, based on the association,a subframe in the set of subframes for transmitting or receiving data onin response to the resource grant, wherein each subframe of the FDDsecond component carrier is associated with a DL subframe of the firstcomponent carrier (block 1406). In one example, block 1406 may beperformed by processor 1708, or processor 1708 coupled to memory 1782.

FIG. 15 shows an example of a process 1500 for decoding or utilizingcontrol information in a wireless network. Process 1500 may be performedby an access node (e.g., a base station, an eNB, etc.), as describedabove, or by some other entity. The access node may receive, from amobile device on an UL subframe, control information associated withtransmissions on a set of DL subframes including TDD subframes and FDDsubframes of the respective first and second component carriers (block1502). In one example, block 1502 may be performed by any combination ofantennas 1734, demodulators 1732, detector 1736, processors 1738, 1740,and/or memories 1739, 1742.

In one design, the access node may determining an association betweenthe set of DL subframes and the UL subframe based on an uplink-downlinkconfiguration of the first component carrier (block 1504). In oneexample, block 1504 may be performed by processor 1740, or processor1740 coupled to memory 1742.

In one design, the access node may decode the control information inaccordance with the association, wherein each DL subframe of the FDDsecond component carrier is associated with an UL subframe of the firstcomponent carrier (block 1506). In one example, block 1506 may beperformed by any combination of processors 1738, 1740, and/or memories1739, 1742.

FIG. 16 shows an example of a process 1600 for sending controlinformation in a wireless network. Process 1500 may be performed by anaccess node (e.g., a base station, an eNB, etc.), as described above, orby some other entity. The access node may determine an associationbetween a DL subframe of the first component carrier and a set ofsubframes including TDD subframes and FDD subframes of the respectivefirst and second component carriers based on an uplink-downlinkconfiguration of the first component carrier (block 1602). In oneexample, block 1602 may be performed by processor 1740 or processor 1740coupled to memory 1742.

In one design, the access node may sending a resource grant to themobile device in the DL subframe, wherein the resource grant schedulestransmission or reception of data by the mobile device with respect to asubframe in the set of subframes based on the association, and whereineach subframe of the FDD second component carrier is associated with aDL subframe of the first component carrier (block 1604). In one example,block 1604 may be performed by any combination of antennas 1734,modulators 1732, processors 1730, 1720, 1740, and/or memories 1712,1742.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable storage medium. Computer-readable storage mediaincludes both computer storage media and communication media includingany medium that facilitates transfer of a computer program from oneplace to another. A storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable storage media cancomprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage,magnetic disk storage or other magnetic storage devices, or any othermedium that can be used to carry or store desired program code means inthe form of instructions or data structures and that can be accessed bya general-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, any connection is properly termed acomputer-readable storage medium. For example, if the software istransmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable storage media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication by a mobiledevice configured for carrier aggregation (CA) of at least a timedivision duplexed (TDD) first component carrier and a frequency divisionduplexed (FDD) second component carrier, comprising: determining anassociation between a set of downlink (DL) subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers and an uplink (UL) subframe of the first component carrierbased on an uplink-downlink configuration of the first componentcarrier; generating control information associated with transmissions onthe set of DL subframes; and sending the control information on the ULsubframe of the first component carrier based on the association,wherein each DL subframe of the FDD second component carrier isassociated with a corresponding UL subframe of the first componentcarrier.
 2. The method of claim 1, wherein the association comprises adistribution of the control information associated with one or more FDDsubframes such that control information for not more than apredetermined number of FDD subframe(s) is associated with the ULsubframe.
 3. The method of claim 2, wherein the predetermined number ofFDD subframe(s) comprises one DL subframe.
 4. The method of claim 1,wherein the UL subframe comprises a closest succeeding UL subframe forproviding hybrid automatic repeat request (HARQ) feedback for thetransmissions on the set of DL subframes subject to a minimum HARQprocessing time.
 5. The method of claim 1, wherein the associationspecifies a distribution of HARQ feedback for the FDD subframes inrelation to the uplink-downlink configuration of the first componentcarrier.
 6. The method of claim 1, wherein the control informationcomprises HARQ feedback bits, and sending the control informationcomprises bundling the HARQ feedback bits for two or more subframes inthe set of DL subframes.
 7. The method of claim 1, wherein theassociation comprises a mapping of HARQ feedback to bits of an ULcontrol channel format.
 8. A mobile device configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier, the mobile device comprising: means for determiningan association between a set of downlink (DL) subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers and an uplink (UL) subframe of the first component carrierbased on an uplink-downlink configuration of the first componentcarrier; means for generating control information associated withtransmissions on the set of DL subframes; and means for sending thecontrol information on the UL subframe of the first component carrierbased on the association, wherein each DL subframe of the FDD secondcomponent carrier is associated with a corresponding UL subframe of thefirst component carrier.
 9. The mobile device of claim 8, wherein theassociation comprises a distribution of the control informationassociated with one or more FDD subframes such that control informationfor not more than a predetermined number of FDD subframe(s) isassociated with the UL subframe.
 10. The mobile device of claim 9,wherein the predetermined number of FDD subframe(s) comprises one DLsubframe.
 11. The mobile device of claim 8, wherein the UL subframecomprises a closest succeeding UL subframe for providing hybridautomatic repeat request (HARQ) feedback for the transmissions on theset of DL subframes subject to a minimum HARQ processing time.
 12. Themobile device of claim 8, wherein the association specifies adistribution of HARQ feedback for the FDD subframes in relation to theuplink-downlink configuration of the first component carrier.
 13. Themobile device of claim 8, wherein the control information comprises HARQfeedback bits, and the means for sending the control information isfurther configured for bundling the HARQ feedback bits for two or moresubframes in the set of DL subframes.
 14. The mobile device of claim 8,wherein the association comprises a mapping of HARQ feedback to bits ofan UL control channel format.
 15. A mobile device configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier, the mobile device comprising: at least one processorconfigured to: determine an association between a set of downlink (DL)subframes including TDD subframes and FDD subframes of the respectivefirst and second component carriers and an uplink (UL) subframe of thefirst component carrier based on an uplink-downlink configuration of thefirst component carrier, and generate control information associatedwith transmissions on the set of DL subframes; a transceiver configuredto send the control information on the UL subframe of the firstcomponent carrier based on the association, wherein each DL subframe ofthe FDD second component carrier is associated with a corresponding ULsubframe of the first component carrier; and a memory coupled to the atleast one processor for storing data.
 16. The mobile device of claim 15,wherein the association comprises a distribution of the controlinformation associated with one or more FDD subframes such that controlinformation for not more than a predetermined number of FDD subframe(s)is associated with the UL subframe.
 17. The mobile device of claim 16,wherein the predetermined number of FDD subframe(s) comprises one DLsubframe.
 18. The mobile device of claim 15, wherein the UL subframecomprises a closest succeeding UL subframe for providing hybridautomatic repeat request (HARQ) feedback for the transmissions on theset of DL subframes subject to a minimum HARQ processing time.
 19. Themobile device of claim 15, wherein the control information comprisesHARQ feedback bits, and the transceiver is further configured to sendthe control information comprises bundling the HARQ feedback bits fortwo or more subframes in the set of DL subframes.
 20. The mobile deviceof claim 15, wherein the association comprises a mapping of HARQfeedback to bits of an UL control channel format.
 21. A computer programproduct, comprising: a computer-readable storage medium comprising: codefor causing at least one computer to determine an association between aset of downlink (DL) subframes including TDD subframes and FDD subframesof the respective first and second component carriers and an uplink (UL)subframe of the first component carrier based on an uplink-downlinkconfiguration of the first component carrier; code for causing the atleast one computer to generate control information associated withtransmissions on the set of DL subframes; and code for causing the atleast one computer to send the control information on the UL subframe ofthe first component carrier based on the association, wherein each DLsubframe of the FDD second component carrier is associated with acorresponding UL subframe of the first component carrier.
 22. A methodof wireless communication by a mobile device configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier, comprising: receiving a resource grant in a DLsubframe of the first component carrier; determining an associationbetween the DL subframe and a set of subframes including TDD subframesand FDD subframes of the respective first and second component carriersbased on an uplink-downlink configuration of the first componentcarrier; and identifying, based on the association, a subframe in theset of subframes for transmitting or receiving data on in response tothe resource grant, wherein each subframe of the FDD second componentcarrier is associated with a DL subframe of the first component carrier.23. The method of claim 22, wherein the association comprises adistribution of subframes scheduled by resource grants such that notmore than a predetermined number of FDD subframes are scheduled by agiven DL subframe of the first TDD component carrier.
 24. The method ofclaim 22, wherein the association comprises a distribution of subframesscheduled by resource grants that minimizes a scheduling delay betweenthe DL subframe on which the resource grant is received and a scheduledsubframe based on the uplink-downlink configuration.
 25. The method ofclaim 24, wherein the resource grant comprises a DL assignment, and theassociation enables scheduling DL subframes of the second componentcarrier corresponding to UL subframes of the first component carrier.26. The method of claim 24, wherein the resource grant comprises an ULgrant, and the association enables scheduling UL subframes of the secondcomponent carrier corresponding to DL subframes of the first componentcarrier.
 27. The method of claim 22, wherein the resource grantschedules a subset of all subframes in a radio frame of the secondcomponent carrier.
 28. The method of claim 22, wherein the determiningthe association is based on an RRC configuration of the mobile devicecomprising a plurality of associations.
 29. The method of claim 22,further comprising receiving downlink control information (DCI), whereinthe determining the association is further based on the DCI, and the DCIcomprises information indicating a designated component carrier and adesignated subframe for the resource grant.
 30. A mobile deviceconfigured for carrier aggregation (CA) of at least a time divisionduplexed (TDD) first component carrier and a frequency division duplexed(FDD) second component carrier, the mobile device comprising: means forreceiving a resource grant in a DL subframe of the first componentcarrier; means for determining an association between the DL subframeand a set of subframes including TDD subframes and FDD subframes of therespective first and second component carriers based on anuplink-downlink configuration of the first component carrier; and meansfor identifying, based on the association, a subframe in the set ofsubframes for transmitting or receiving data on in response to theresource grant, wherein each subframe of the FDD second componentcarrier is associated with a corresponding DL subframe of the firstcomponent carrier.
 31. The mobile device of claim 30, wherein theassociation comprises a distribution of subframes scheduled by resourcegrants such that not more than a predetermined number of FDD subframesare scheduled by a given DL subframe of the first TDD component carrier.32. The mobile device of claim 30, wherein the association comprises adistribution of subframes scheduled by resource grants that minimizes ascheduling delay between the DL subframe on which the resource grant isreceived and a scheduled subframe based on the uplink-downlinkconfiguration.
 33. The mobile device of claim 32, wherein the resourcegrant comprises a DL assignment, and the association enables schedulingDL subframes of the second component carrier corresponding to ULsubframes of the first component carrier.
 34. The mobile device of claim32, wherein the resource grant comprises an UL grant, and theassociation enables scheduling UL subframes of the second componentcarrier corresponding to DL subframes of the first component carrier.35. The mobile device of claim 30, wherein the resource grant schedulesa subset of all subframes in a radio frame of the second componentcarrier.
 36. The mobile device of claim 30, wherein the means fordetermining the association is further configured for determining basedon an RRC configuration of the mobile device comprising a plurality ofassociations.
 37. A mobile device configured for carrier aggregation(CA) of at least a time division duplexed (TDD) first component carrierand a frequency division duplexed (FDD) second component carrier, themobile device comprising: a transceiver configured to receive a resourcegrant in a DL subframe of the first component carrier; at least oneprocessor configured to: determine an association between the DLsubframe and a set of subframes including TDD subframes and FDDsubframes of the respective first and second component carriers based onan uplink-downlink configuration of the first component carrier, andidentify, based on the association, a subframe in the set of subframesfor transmitting or receiving data on in response to the resource grant,wherein each subframe of the FDD second component carrier is associatedwith a corresponding DL subframe of the first component carrier; and amemory coupled to the at least one processor for storing data.
 38. Themobile device of claim 37, wherein the association comprises adistribution of subframes scheduled by resource grants such that notmore than a predetermined number of FDD subframes are scheduled by agiven DL subframe of the first TDD component carrier.
 39. The mobiledevice of claim 37, wherein the association comprises a distribution ofsubframes scheduled by resource grants that minimizes a scheduling delaybetween the DL subframe on which the resource grant is received and ascheduled subframe based on the uplink-downlink configuration.
 40. Themobile device of claim 39, wherein the resource grant comprises a DLassignment, and the association enables scheduling DL subframes of thesecond component carrier corresponding to UL subframes of the firstcomponent carrier.
 41. The mobile device of claim 39, wherein theresource grant comprises an UL grant, and the association enablesscheduling UL subframes of the second component carrier corresponding toDL subframes of the first component carrier.
 42. The mobile device ofclaim 37, wherein the resource grant schedules a subset of all subframesin a radio frame of the second component carrier.
 43. The mobile deviceof claim 37, wherein the at least one processor is further configured todetermine the association based on an RRC configuration of the mobiledevice comprising a plurality of associations.
 44. A computer programproduct, comprising: a computer-readable storage medium comprising: codefor causing at least one computer to receive a resource grant in a DLsubframe of the first component carrier; code for causing the at leastone computer to determine an association between the DL subframe and aset of subframes including TDD subframes and FDD subframes of therespective first and second component carriers based on anuplink-downlink configuration of the first component carrier; and codefor causing the at least one computer to identify, based on theassociation, a subframe in the set of subframes for transmitting orreceiving data on in response to the resource grant, wherein eachsubframe of the FDD second component carrier is associated with acorresponding DL subframe of the first component carrier.
 45. A methodof wireless communication by an access node supporting carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier for a mobile device, comprising: receiving, from themobile device on an uplink (UL) subframe, control information associatedwith transmissions on a set of downlink (DL) subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers; determining an association between the set of DL subframes andthe UL subframe based on an uplink-downlink configuration of the firstcomponent carrier; and decoding, by the access node, the controlinformation in accordance with the association, wherein each DL subframeof the FDD second component carrier is associated with an UL subframe ofthe first component carrier.
 46. The method of claim 45, wherein theassociation comprises a distribution of control information associatedwith subframes of the second component carrier such that controlinformation for not more than a predetermined number of FDD subframe(s)is associated with the DL subframe.
 47. The method of claim 45, whereinthe UL subframe comprises a closest succeeding UL subframe for providinghybrid automatic repeat request (HARQ) feedback for the transmissions onthe set of DL subframes subject to a minimum HARQ processing time. 48.The method of claim 45, wherein the control information comprisesbundled HARQ feedback, and decoding the control information comprisesdecoding the HARQ feedback for determining a status of the associatedone or more FDD subframes.
 49. The method of claim 45, wherein theassociation comprises a mapping of HARQ feedback to bits of an ULcontrol channel format.
 50. An access node configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier, comprising: means for receiving, from the mobiledevice on an uplink (UL) subframe, control information associated withtransmissions on a set of downlink (DL) subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers; means for determining an association between the set of DLsubframes and the UL subframe based on an uplink-downlink configurationof the first component carrier; and means for decoding, by the accessnode, the control information in accordance with the association,wherein each DL subframe of the FDD second component carrier isassociated with an UL subframe of the first component carrier.
 51. Theaccess node of claim 50, wherein the association comprises adistribution of control information associated with subframes of thesecond component carrier such that control information for not more thana predetermined number of FDD subframe(s) is associated with the DLsubframe.
 52. The access node of claim 50, wherein the UL subframecomprises a closest succeeding UL subframe for providing hybridautomatic repeat request (HARQ) feedback for the transmissions on theset of DL subframes subject to a minimum HARQ processing time.
 53. Theaccess node of claim 50, wherein the control information comprisesbundled HARQ feedback and decoding the control information comprisesdecoding the HARQ feedback for determining a status of the associatedone or more FDD subframes.
 54. The access node of claim 50, wherein theassociation comprises a mapping of HARQ feedback to bits of an ULcontrol channel format.
 55. An access node configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier for a mobile device, comprising: a transceiverconfigured to receive, from the mobile device on an uplink (UL)subframe, control information associated with transmissions on a set ofdownlink (DL) subframes including TDD subframes and FDD subframes of therespective first and second component carriers; at least one processorconfigured to: determine an association between the set of DL subframesand the UL subframe based on an uplink-downlink configuration of thefirst component carrier, and decode, by the access node, the controlinformation in accordance with the association, wherein each DL subframeof the FDD second component carrier is associated with an UL subframe ofthe first component carrier; and a memory coupled to the at least oneprocessor for storing data.
 56. The access node of claim 55, wherein theassociation comprises a distribution of control information associatedwith subframes of the second component carrier such that controlinformation for not more than a predetermined number of FDD subframe(s)is associated with the DL subframe.
 57. The access node of claim 55,wherein the UL subframe comprises a closest succeeding UL subframe forproviding hybrid automatic repeat request (HARQ) feedback for thetransmissions on the set of DL subframes subject to a minimum HARQprocessing time.
 58. The access node of claim 55, wherein the controlinformation comprises bundled HARQ feedback and decoding the controlinformation comprises decoding the HARQ feedback for determining astatus of the associated one or more FDD subframes.
 59. The access nodeof claim 55, wherein the association comprises a mapping of HARQfeedback to bits of an UL control channel format.
 60. A computer programproduct, comprising: a computer-readable storage medium comprising: codefor causing at least one computer to receive, from a mobile device on anuplink (UL) subframe, control information associated with transmissionson a set of downlink (DL) subframes including TDD subframes and FDDsubframes of the respective first and second component carriers; codefor causing the at least one computer to determine an associationbetween the set of DL subframes and the UL subframe based on anuplink-downlink configuration of the first component carrier; and codefor causing the at least one computer to decode, by the access node, thecontrol information in accordance with the association, wherein each DLsubframe of the FDD second component carrier is associated with an ULsubframe of the first component carrier.
 61. A method of wirelesscommunication by an access node supporting carrier aggregation (CA) ofat least a time division duplexed (TDD) first component carrier and afrequency division duplexed (FDD) second component carrier for a mobiledevice, comprising: determining an association between a DL subframe ofthe first component carrier and a set of subframes including TDDsubframes and FDD subframes of the respective first and second componentcarriers based on an uplink-downlink configuration of the firstcomponent carrier; and sending a resource grant to the mobile device inthe DL subframe, wherein the resource grant schedules transmission orreception of data by the mobile device with respect to a subframe in theset of subframes based on the association, and wherein each subframe ofthe FDD second component carrier is associated with a DL subframe of thefirst component carrier.
 62. The method of claim 61, wherein theassociation comprises a distribution of subframes for scheduling byresource grants that minimizes a scheduling delay between the DLsubframe and a scheduled subframe based on the uplink-downlinkconfiguration.
 63. The method of claim 61, wherein the resource grantcomprises a DL assignment, and the association enables scheduling DLsubframes of the second component carrier corresponding to UL subframesof the first component carrier.
 64. The method of claim 61, wherein theresource grant comprises an UL grant, and the association enablesscheduling UL subframes of the second component carrier corresponding toDL subframes of the first component carrier.
 65. The method of claim 61,wherein the association comprises one or more subframe offsets relativeto a subframe number of the DL subframe.
 66. The method of claim 61,sending an RRC configuration message indicating a selection of theassociation from a plurality of associations.
 67. An access nodeconfigured for carrier aggregation (CA) of at least a time divisionduplexed (TDD) first component carrier and a frequency division duplexed(FDD) second component carrier, the access node comprising: means fordetermining an association between a DL subframe of the first componentcarrier and a set of subframes including TDD subframes and FDD subframesof the respective first and second component carriers based on anuplink-downlink configuration of the first component carrier; and meansfor sending a resource grant to the mobile device in the DL subframe,wherein the resource grant schedules transmission or reception of databy the mobile device with respect to a subframe in the set of subframesbased on the association, and wherein each subframe of the FDD secondcomponent carrier is associated with a DL subframe of the firstcomponent carrier.
 68. The access node of claim 67, wherein theassociation comprises a distribution of subframes for scheduling byresource grants that minimizes a scheduling delay between the DLsubframe and a scheduled subframe based on the uplink-downlinkconfiguration.
 69. The access node of claim 67, wherein the resourcegrant comprises a DL assignment, and the association enables schedulingDL subframes of the second component carrier corresponding to ULsubframes of the first component carrier.
 70. The access node of claim67, wherein the resource grant comprises an UL grant, and theassociation enables scheduling UL subframes of the second componentcarrier corresponding to DL subframes of the first component carrier.71. The access node of claim 67, further comprising means for sending anRRC configuration message indicating a selection of the association froma plurality of associations.
 72. An access node configured for carrieraggregation (CA) of at least a time division duplexed (TDD) firstcomponent carrier and a frequency division duplexed (FDD) secondcomponent carrier, the access node comprising: at least one processorconfigured to: determine an association between a DL subframe of thefirst component carrier and a set of subframes including TDD subframesand FDD subframes of the respective first and second component carriersbased on an uplink-downlink configuration of the first componentcarrier; a transceiver configured to send a resource grant to the mobiledevice in the DL subframe, wherein the resource grant schedulestransmission or reception of data by the mobile device with respect to asubframe in the set of subframes based on the association, and whereineach subframe of the FDD second component carrier is associated with aDL subframe of the first component carrier; and a memory coupled to theat least one processor for storing data.
 73. The access node of claim72, wherein the association comprises a distribution of subframes forscheduling by resource grants that minimizes a scheduling delay betweenthe DL subframe and a scheduled subframe based on the uplink-downlinkconfiguration.
 74. The access node of claim 72, wherein the resourcegrant comprises a DL assignment, and the association enables schedulingDL subframes of the second component carrier corresponding to ULsubframes of the first component carrier.
 75. The access node of claim72, wherein the resource grant comprises an UL grant, and theassociation enables scheduling UL subframes of the second componentcarrier corresponding to DL subframes of the first component carrier.76. The access node of claim 72, wherein the transceiver is furtherconfigured to send an RRC configuration message indicating a selectionof the association from a plurality of associations.
 77. A computerprogram product, comprising: a computer-readable storage mediumcomprising: code for causing at least one computer to determine anassociation between a DL subframe of the first component carrier and aset of subframes including TDD subframes and FDD subframes of therespective first and second component carriers based on anuplink-downlink configuration of the first component carrier; and codefor causing at least one computer to send a resource grant to the mobiledevice in the DL subframe, wherein the resource grant schedulestransmission or reception of data by the mobile device with respect to asubframe in the set of subframes based on the association, and whereineach subframe of the FDD second component carrier is associated with aDL subframe of the first component carrier.